When Aang first sees her, he thinks back to the vision of that girl he saw in the swamp, and he automatically deduces that this blind earthbender is not meant to be his earthbending sifu. The girl from his vision was small and delicate, all soft curves; the girl he sees is all hard, rough edges and, though small, is the farthest thing possible from delicate. She's wearing dirty, wrinkled boys' clothes, not the white dress from his vision, but he can't expect her to wear the same dress all the time, so he lets this one slide. Her voice – loud, rude, and obnoxious as opposed to the delicate, chime-like laugh from his vision – only reaffirms his belief.
And then she bends. It takes another bender to see how graceful she really is when she earthbends – even though "graceful" is probably the last thing she wants to be. Everyone's awed by her skill, the way she single-handedly defeats a man who defeated literally all other possible opponents despite not being able to see, but Aang sees something else there. The rough edges soften, and, for just a small, tiny moment, Aang sees the girl from his vision – the beautiful girl in the white dress.
He doesn't think when he leaps into the arena. "Do people really want to see two little girls fighting out here?" the girl asks arrogantly, smirking at him.
Aang holds up his hands defensively. "I don't really want to fight you. I want to talk to you." He steps toward her, and her smirk widens, and he finally knows.
She's the one.
Believe it or not, I shipped Taang before I shipped Zutara. I always thought there was something sweet and romantic about how Aang first saw Toph in a vision and then saw her in the Earth Rumble and was all "She's the one, Katara, SHE'S THE ONE!" … and then another reason to ship Zuko and Katara together is because they're both the worst cockblocks EVER. Almost every single legitimate Taang moment in the series is cockblocked by Katara. It's really annoying.
Anyway, PLEASE REVIEW!