Twilight Sparkle never thought she'd ever fall in love with anypony. None of the stallions in Ponyville were attractive, and her one-night-stand with Big Macintosh wasn't what she'd expected at all. She'd heard rumors about her friends having affairs with each other, but Spike was a big gossip and the young princess didn't believe him when he blabbered on about it. One fateful day, she stumbles across Applejack's well hidden diary and, despite herself, she reads it. She discovers her friend's burning desire for her, and she feels something inside she's never felt before.
On the night of the Mane Six's fourth Grand Galloping Gala, Twilight pretties herself up even more than usual in an effort to catch her friend's attention, and soon notices that Applejack can't seem to keep her eyes off of her.
The princess manages to slip away from Celestia and conveniently locate herself in the empty, dark spare ballroom used mainly as a storage unit for unused palace equipment, making sure Applejack saw her as she went.
Things happen, confessions are made, and Twilight is finally able to say, "I have a very special somepony."