"Of course not." Sephiroth tries to make his voice as soothing as possible. He's not sure that comforting people has ever been a skill he's excelled at, but he draws on as much of his years of experience with Angeal as possible. Angeal knows how to comfort people. If he can mimic him well enough... "You're here, with me."

And while to Cloud that might qualify as its own nightmare, Sephiroth honestly thinks that for anyone who's been subject to Hojo, even his murderous self when puppeted by Jenova would be considered a marked improvement. And Cloud...genuinely does seem to recognize that he isn't Jenova, either. He simply hopes that Cloud holds on to that awareness while his mind is already under such strain.