It's got everything to do with it!

[Sora looks up but keeps his hand over the spot on Vanitas' chest where he can feel the heartbeat.]

I know it might seem really far away. But your heartbeat is proof that someday you'll have your own heart that's all yours someday. It proves that you can have it. Just like anyone else.

[He leans forward to nuzzle the other boy.]

I know you've heard stuff like that before. But it still means a lot to me to know that too. Even if someday we've gotta fight for it to happen.