[There's a lot neither of them should promise right now. Ain shouldn't entertain the idea of being in love with a human-passing alien. Said human-passing alien shouldn't entertain the idea of them ever living together in a domestic, not-on-the-run situation. Ain shouldn't sink his talons in any deeper than he has them, even if the thought of giving Vash up sickens him to his core. Yet here they are, cuddled up in a hot spring beneath the stars, making promises that Ain clings to with every fiber of his being because he doesn't know how to let go.]

I still want to have a house with you in general. I want to learn to cook for you... haha, is that silly?

[Is it silly to want to become a malewife for them? Ain has no ability in the wife department, he's pretty useless if he's not casting magic — but still.]

I told you already that we'll get there. I'm not giving up on that yet, because I want to keep you and all. Because you're mine, and I'm yours.

[just

skirting the edge of what those words mean, so far. "Yours" and "mine" but he wants it to flow deeper than their bond they have now.]