[Dante frowns. He really is trying to give this the weight it deserves, even as hard as it is to piece together fragments of memory that aren't even his own.]

Hold on, I'm gonna need a little more detail. What do you mean, he wanted to see you fall? Was that the first... monster you'd ever killed? Or was it some sort of outlier that he was a person who'd turned into one?

[Sure, he remembers killing tons of Heartless. But he also remembers how each of them was once a person, and how destroying a Heartless released the heart that had been trapped inside of it. It was what had needed to be done, right?]

What makes you so sure he was suffering?