So I just finished playing through kh2 nd my ps2 hates me lol. Anyway when fighting xemnas he catches sora in that orb thing. Before he does that he says something like," can you spare a heart" now as I'm typing this I'm slowly realizing that I'm probably just overthinking it, but do you think xemnas knows that sora could spare a heart? You know since Ven's heart was in roxas and right before the xemnas fight roxas goes back into sora....wow I'm just sorta rambling now haha.

He knows that Ven is in Roxas, so yeah. Most likely.

 

But his line in KH2 is most likely just referring to Xemnas not having one and, well, Sora having one.

you know i was curious about it to.but honestly i think it was just coincidence man.

Even if it was a coincidence I see no problem in reading a bit extra stuff into it.

In the intro of the game in kh2, when roxas is talking to xemnas, Xemnas says that he "looks like him", at first I thought it was sora, but now I think its probably ven

we dont know sure cause xemnas cant remember ven from xehanorts past