He hesitates. Debates, for a moment. Should he even try...? But Cloud asked, and while there's not much Sephiroth can give him, honesty is perhaps the bare minimum.

"Jenova." He says it simply. "I...or whatever's left of me...have been doing what Jenova wants, ever since that day in Nibelheim. I am...whatever part of Sephiroth that Jenova is not. I don't want the same things. I never have."