Hey, fanon! Guess what!
"You make me feel like I have a heart" is NOT a canon line!
First of all, nobody ever actually says that in the canon. Axel says something like it, but he never spits out those exact words.
Don't believe me? Well,
here it is. (And here's the obligatory spoiler warning, which applies for the rest of the rant.)
What's more, it is never used as a confession of love or anything remotely resembling it. Axel never says it to Roxas, or to any other nobody for that matter. He says it to Sora, and he only says it when he's dying. That's not a confession of love. That's a "let me get this off my chest before I go not-so-gently into that great night" moment.
And hey: just so you know, no other member of the Organization uses that line either. EVER. That would be as big a breach of canon as one of them asking if somebody had "got it memorized".
In conclusion: quit using the line. We're all sick to death of you screwing up what used to be a moving scene. Now, thanks to your unwanted interference and overuse, it's just annoying. If you can't treat the fandom right, then get the hell out. We will not miss you.
Sincerely hoping that somebody out there knows that "canon" is not an old-fashioned form of heavy artillery,
Yamiko