Sorry for getting all ranty, I just think if any couples are going to make it to the very end, I think at least Black Sun and Arctic Water
BlackSun has always given off endgame vibes to me, and Renora definitely has, too.
I’ve always loved Arctic Ocean, but I don’t know if they’re as definitely likely to make it as the others are. Weiss’s feelings for Neptune are very explicitly stated in the show, and Neptune definitely cares about Weiss on some level (being the one to cry her name out in the big v3 fight, admitting he thinks she’s nice enough though he doesn’t really know her well enough to say he likes her in v2), but they haven’t made any tangible steps towards getting together, and it could just as easily end up playing out as a passing crush on Weiss’s end. Kind of hard to hold onto an infatuation when you’re separated and going through the stuff Weiss goes through, though it could rekindle when they meet again (I certainly would enjoy that).