Author's Notes: Since some people seem confused about 3 in the last chapter (and that's my fault for not clarifying), I'm posting what was originally 3. Hopefully this will clear everything up, but if there are still any questions, feel free to ask!
Her third engagement is arranged when she is nineteen, and this time, it's of her own free will.
His name is Hotaru (firefly, he tells her). He reminds her of a firefly, too—swift, fluttery, bright, lighting up her world. People tell her she's so lucky, that he's such a handsome man, that they will have such a happy life together.
And she believes it.
She's so very much in love, like she never thought she could be. She loves everything about him, from the way his smile translates through his vibrations to the way he always knows when she needs help but is too stubborn to admit it. He is sweet and innocent and kind and funny and smart with her when she's smart with him.
He is perfect. He is nothing like him.
Him. Sokka. Her best friend. Her once-upon-a-dream lover.
She swore to herself, a long time ago, that her childish crush on the boy would never be anything more than a childish crush. Of course, it didn't turn out that way, just as it never does.
She still sees him now, every once in a while, and he's still one of her dearest friends. And he still, she is reminded on his every return, holds a small part of her heart in his hands. But the majority of her heart, the heart still intact, has already been captured by the pretty words and kind actions of the boy who lives three houses down.
She introduces them once, just to see how they will react to each other.
They all go out to eat at her favorite restaurant. Sokka orders her favorite dish, just like he always used to do, and shares it with her, just like they always used to do. She can tell Hotaru is jealous of the attention she gives her long-lost friend, but he ignores it and instead asks questions: how they met, of their adventures with the Avatar, if Sokka has a girlfriend. Her best friend scowls at the last one.
When their little party is over, Toph leaves Hotaru on his doorstep to contemplate the kiss she left on his lips. Sokka she merely drags back to her house and drops on the couch. He's unusually quiet, and she waits for him to say something, entertaining herself with Bending her meteorite bracelet.
When he finally speaks, it's to say, "I don't like him."
Toph grins a self-righteous grin and replies, "Good."
She is engaged the next day.
The wedding is set for within the month. Her suitor has met everyone of importance. Katara finds him ridiculously charming ("if only you could see how handsome he is, Toph, you'd fall in love all over again!"). Aang is enraptured now that he has someone new to entertain with all his old Airbending tricks. Appa and Momo seem to squeak and grunt their approval. Even Sokka grudgingly admits he's an okay guy.
She's never been happier, Toph thinks.
And then, just like it has the habit of doing, Toph's world collapses in on itself.
A small group of Fire Nation rebels are attacking the western coast of the Earth Kingdom. The Earth King is taking a small group of sixth regimen soldiers to deal with the problem.
Hotaru never told her he was in the army.
He's departing in a week. It's not enough time to move up the wedding. It's not enough time for her to say everything she wants to say to him. It's not enough time.
Because she knows, deep within her, that there's the very real possibility that he might not come back.
"Don't worry about me," he says, kissing her cheek as she scowls. "You know how tough I am. You know how much I love you."
She knows, but that's not enough to keep him alive.
When he dies in a Fire Nation rebel raid, she swears never to fall in love again.
Of course, it never works out that way, does it?