“Sweetie Belle, do you... love your sister, Rarity?”
“Of course! She’s the bestest big sister I could ever have!”
“It’s not just because she’s your sister, is it?”
“N...no? What do you mean?”
“Well, what if she wasn’t your sister? What would you think of her? Just pretend there’s a pony who isn’t your sister called... Charity, who is just like Rarity.”
“Well, Charity doesn’t take care of me though. Rarity does.”
“Suppose she did though? Just as much as Rarity does. And she has a boutique, where she makes the most beautiful dresses.”
“Rarity is such an amazing pony. So many ponies love her dresses already, and she keeps working hard to make them better and better! She’s so good at everything. It’s... kind of intimidating sometimes. She’s just so incredible that I wish I could be like her.”
“Well... back to Charity though. What if she’s every bit as incredible as Rarity? Could you love her, even though she’s not your sister?”
“...does she love me?”
“More than she knows, Sweetie. Charity turned down all the fanciest ponies in Canterlot, just so she could spend more time with you. She... covered herself in mud just so she could run with you in the Sisterhooves Social.”
“So... pretty much like Rarity?”
“Yes, pretty much like Rarity.”
“Is this somepony I should know about?”
“Nnno, it’s just a little thought experiment. I just want to know if you could love somepony like Rarity, even if she isn’t your sister.”
“I suppose I could? I don’t know for sure until I meet her.”
“That’s a very wise attitude, Sweetie Belle. But yes, you do know her. What I wanted to know was... if Rarity wasn’t your sister, would you still love her?”
“Are you kidding? Of c҉ourse I would! I would love Rarity no matter what, even if she’s a donkey! She loves me so much, and she’s always there for me, and... she’s just... she’s special to me. It’s not just because she’s my sister. It’s because she’s so important to me!”
“I think you need to tell Rarity that. It’s something she really needs to know, I’m afraid.”
“What do you mean?”
“Just... tell her that you would still love her, even if she wasn’t your sister. Tell her you love her because she’s so important to you, and it doesn’t matter if she’s your sister or not. I’ve been trying to tell her that myself, but I just can’t get through to her. She needs to hear it from you. She thinks you only love her because she’s your sister, and I’m worried about her. So could you please just... tell her that? Even if it seems obvious, she just needs you to tell her.”
“What is this about, Miss Twilight?”
“I... I don’t want to say. I just want you to know that Rarity’s hurting and afraid, and she needs her... sister to reassure her that you would still love Rarity even if Rarity weren’t your sister. That’s all I ask. And um... keep a box of tissues handy.”
“Well, okay Miss Twilight, but you’re kind of scaring me. She is my sister, right?”
“Would it matter if she wasn’t?”
“...I’ll go tell her.”
...
“Rarity, am I adopted???”
“What? Don’t be silly! Who put such a ridiculous notion in your head?”
“Um... nopony really, I was just wondering. Are you sure?”
“I’m very sure, darling. Now run along and play while I fix you three a nice afternoon snack.”
“...you know I love you, right?”
“Oh Sweetie, thank you! You are a wonderful filly for saying such things to others. I want you too to know that I love you so much.”
“T-thanks... I really do love you though. You’re my favoritest sister in the whole world!”
“Y-yes, well I’m quite honored that you would think so highly of me.”
“If I wasn’t—”
“...yes, Sweetie?”
“I just... wanted to let you know that you’re important to me, and an amazing pony, and that’s why I love you. Because you care about me, and... stuff. It’s not just because you’re my sister, even though I love being sisters with you.”
“Sweetie...?”
“I’m just saying I would still love you just as much, even if you weren’t my sister.”
“...Twilight set you up to this, didn’t she.”
“Nnnno? ...yes.”
“I’ll be right back, Sweetie.”
...
R: Come down from that bookshelf, and fight me like a mare!
T: You said one week! It’s been one week! I had to do something!
S: Rarity, please! Leave her alone! She didn’t say anything bad!
R: I suppose our friendship means nothing to you! To expose my darkest secrets for all to see?
T: I didn’t tell her! I just told her to talk with you, because you needed somepony to talk with you!
S: She didn’t tell me! She just said to—oh, right, what she said.
R: And I suppose she came up all on her own with that little notion that I’m not her sister?
T: I just—
S: I don’t care if you’re my sister! Rarity, why do you think I would stop loving you? You’re the best sister to me in the whole world! You’re an amazing pony! I r-really look up to you. You take care of me, and you help me when I need it, and you—and you don’t help me when I don’t need it. Even if you were a donkey, you would still be Rarity, the best sister I ever had! And the only sister, but a really, really special pony!
R: Even if I was your.........
S: I love you, Rarity. Please, stop being so sad. I don’t even know what’s wrong. If you’d just tell me...!
R: I... I’m sorry.
...
R: UNLOCK THE DOOR THIS INSTANT, TWILIGHT SPARKLE
T: No! You need to tell her! Right now!
R: I will eat your eyeballs for breakfast!
T: Do you really think it matters anymore?
R: Not after you destroyed any hope of me keeping everything nice and ...pleasant!
S: What is the issue here? I said I don’t care, so what’s the problem?
R: Oh, Sweetie. I’m afraid, I’m... okay I will tell you. It’s just... it’s not easy for me, alright? But I will tell you, because I do care about you and... you have every right to know.
R: When I was a filly, not much older than you in fact, I had the... a device installed that... I believe I have called it a erm... “murder coil?”
S: You what?! Then why did you get mad at me! You—
T: Sweetie Belle, let her finish.
R: Thank—fine. I had a... a young love let’s say. He was a Canterlot unicorn who was so sophisticated and worldly, and I was sure he... loved me. At any rate, we... he convinced me to try an... IUD, so that we could consummate our... relationship.
S: What does consummate mean?
T: It means sex.
S: Oh.
R: I wasn’t so foolish to think that it would be a good idea to get pregnant at that age, even by one such as him. But, with it... installed, I did have a good half a month of... bliss, before my—before Mother found out what I was doing. She and I—disagreed on whether I and ...he should have been together. We fought it out, and she... found out I had a murder coil. I found out I had a murder coil. I didn’t even know it was the same thing, but our pastor was adamantly clear that it was. You wouldn’t know him, the predecessor to Reverent Tightbottom.
R: So, to save my life, my... parents thought, the device was removed from my womb, and I was free to... live my life. I’d spent half my estrus in wanton lust though, without any consequences, and it was—it was really hard. We met, he and I. I... I just wanted him so badly. I’m sorry Sweetie, but I was a fallen mare. I had... sex out of wedlock, and felt no regret or shame, only embarassment. I tried to see things as the grownups did, but I simply couldn’t ignore that siren call. You know what I speak of.
S: Well, I guess. But I don’t know if it’s always this bad.
R: No, it’s... not. I had no excuse, really. But I continued to meet with him, even after the device was removed, and well... at a very young age, I... I ended up with child. I’m sorry Sweetie I’ve wanted to tell you so badly, but I was just... I’ve just been so afraid. I’m not the good mare you know and love. I’m... flawed, broken. I’ve done things that I’m not proud of, and anypony who found out... we managed to keep it a family secret, so to speak, so ponies think that we’re just s-sisters. I just couldn’t burden you with that secret. You were such a sweet young filly, I just couldn’t bear to see you—know. They... they promised to raise you, but it wasn’t their responsibility, and once I started giving milk I knew I was... stuck.
R: So, I took responsibility, and... I’m sorry Sweetie. I’m not your sister. I meant to tell you as you went into your first estrus, but it’s just been so hard. With the miscarriage, I felt like... like it could have been you I lost. That you could have felt what I felt when... when I thought about ending my pregnancy. And when I found out you had the device that... I wasn’t allowed to have, I just got... jealous. Yes, I was being the jealous older sister, just like I always wanted, and I almost hurt you as badly as I’ve been hurt.
“So Mom and Dad...?”
“Are your grandparents, yes.”