Early one morning, as the sun and the moon were exchanging places over the land of Equestria, Princess Celestia and her younger sister Luna were sharing their first meal together in ages. A silence filled with heavy tension seemed to have befallen the two pegasus unicorns, until Luna finally summoned up the courage to speak. She still wasn't fully comfortable speaking to the one responsible for her thousand-year exile to the moon, and it would be a long time before she finally did feel that comfort. Nonetheless, Luna had a question that she needed answering sooner rather than later.
"Yes, what is it, Luna? Before you do, though, please allow me to remind you that there is no need to refer to me in such a formal manner, you know; we are sisters, after all."
"Sorry about that."
"It's perfectly fine. Now, what is it you want to ask me?"
Luna took in a deep breath to calm her nerves. "I'm very confused about something: what exactly is it that you're supposed to feel when you think you're in love, or at least attracted, to somepony?"
"WHAT?" Celestia was so taken aback by this unexpected question that she nearly found herself choking on a piece of celery halfway down her throat. While waiting for her elder sister to regain her composure, Princess Luna fidgeted nervously back and forth in her seat. She had never told anyone about her secret affections, and she hoped that her elder sister would take it well. Her little pony heart was beating loudly against her chest.
"It's been really bothering me alot lately, Celestia,"
"Luna...you...you don't understand about love? It's nothing too difficult to understand, dear. It's been a very long time since your baby years when issues like that were a problem!" Celestia raised a hoof to her mouth and coughed. A look outside the window revealed the sky to be illuminated with a beautiful light-orange hue. There were only a few clouds present, but once the pegasus ponies woke up there were bound to be more ahead.
"Sister, you know better than anypony that I've been stranded on the moon for the past thousand years filled with nothing but loneliness and hatred. I can't help it if I'm behind most of the other ponies!" The smaller pony snapped back. Luna didn't necessarily intend to do this, but her words were filled with a hidden malice towards her sibling. Just thinking back to the days of her lengthy exile made Luna want to break out sobbing. Celestia noticed this immediately and a pang of guilt followed soon after.
"I'll...try to help you the best I can, Luna."
"Love, though, is not exactly something that can be easily explained in any sense of the word. You care alot about a person when you love them, and it's in a way that goes beyond friendship, but it's very similar to it. You want to be with them almost all of the time, and you can't stop thinking about them. You want to know more about them and do things together. Some ponies these days have a hard time telling the difference between love and lust, sad as it is to say. Love isn't something that you can be irresponsible about; it takes both ponies to accept each other's love for the bond to form."
Luna had been writing down everything Celestia was saying. "It makes sense, when you say it like that!"
"Even though I am a princess, I can still make mistakes. What I think about love could be very different from your interpretation of it. Just be careful about how you handle it."
"Okay! Thank you so much, Celestia!"
"You're welcome! By the way," Celestia had been waiting the entire time to ask her own question in return, "Just WHO is it that you have become smitten for, my dear sister? He's a very lucky pony." She couldn't hide the smile that was forming on her lips.
Luna giggled to herself, looking very pleased but also bashful. Images of her secret crush floated about in her head. "I don't really know her name, but-" Realizing the bomb she had just dropped, Luna covered her mouth with both of her hooves. Celestia's expression showed no sign of faltering, fortunately.
"To be perfectly honest, Luna, I'm less shocked about you being attracted to fillies than about you being confused on things like love and friendship."
'I would tell her that I suspected it all along, but that might be mean...' Celestia thought to herself, at the same time saying, "I'll accept you for what you are, no matter what it is, because you are my beloved little sister, and I want to make things right between us again."
"Oh, Celestia..." Luna felt like crying again. Celestia gave her sister a comforting pat on the shoulder with her hoof.
"In that case, who is the girl that you feel such passionate emotions for?"
"She's actually someone we see alot. Her name is-"
Before Princess Luna could speak the name of the one who had captured her heart, a loud crash was heard coming from the other room. It was around the same time that the mail-pony arrived every day except Sunday. Luna jumped to her feet and darted out towards the source of sound without a word. The poor pony looked absolutely terrified, but probably more so for who had caused the crash rather than the crash itself. Celestia was about to follow after her, when something very strange came to her attention.
'Wait a minute...as far as I know, Luna has never left the castle even once. The poor girl was always shy, and being alone for a thousand years hasn't done any good on her psyche. She hardly ever talks to any of the guardsponies or the maids. If she doesn't interact with people much, then WHO could she have fallen in love with?'
"Oh my goodness, are you okay?" Luna's shrieking voice echoed through the spacious dining room. She sounded frightened.
Celestia peeked her head out, and what she saw made her blood run cold; Princess Luna was desperately trying to help lift a gray, blonde-haired pegasus to her feet. The winged pony's wide eyes were crossed and unfocused, and she was carrying a bag of letters strung over her back on a saddle. Celestia recognized the pony as Derpy Hooves, a mail-pony who seemed to have an extreme mental disorder. Although Derpy only came on Tuesdays and Thursdays to deliver mail to Celestia, she never once was able to arrive at the castle without causing some kind of property damage or accidentally dropping an important parcel. Personally, Celestia didn't think Derpy should be allowed to work as a mail-pony anymore, but trying to actually get her fired would be overstepping her boundaries.
Celestia turned her attention to Luna, and could see the compassion and worry for Derpy that was evident in her sister's eyes. She was even blushing as she held Derpy's body in between her front legs. It was all so obvious to Celestia now.
'Dammit...! Why did it have to be Derpy?'