Originally Posted by
Majesty
Because he knows she is really the only woman that could Ultimately save Bruce from himself, and ultimately make him happy. Bruce said himself, Diana to him is the 'perfect' woman, and the fact she doesn't even know it makes her even more so.
If Bruce had one chance at actual 'happiness' in a relationship, the only person for him at the end of the day would be Diana. He knows that, Diana deep down knows that, as does Superman. (When they all get to that point in their careers and such).
Not early on, and probably not for a very long time in this New 52. But it always seems to come back around to them eventually, as we all know Clark is going to go to Lois eventually.
But that was interesting how Superman always 'knew' that there was something 'special' between Diana and Bruce, even though both through duty or whatever moral code wouldn't act upon it, except in those 'few' moments when nothing else seemed to matter but one another. Those moments, though rare, Clark saw right through them both and knew what they wanted, but never acted upon having, at least not then.
If Bruce ends his life there, on Paradise Island, in Wonder Woman's arms, that is a fitting end. As I said, I'd be satisfied if we never saw "Bruce Wayne" again after that. I Can't say that about many superheroes, but that 'end' for him is just too perfect, it is the sendoff he truly deserves.