Cole's used to keeping secrets. Heck, he's kept secrets for about half the people he knew back home at various points. So, at Peridot's request, he nods like it's the easiest thing in the world.

"A different Peridot did all that anyway. You wouldn't do it now." And really, that's what matters in his mind. She's never going back to the Peridot of old, the one who served the diamonds and tried to stop the Steven. And if it hurts her to bring it up, then the simple solution is not to bring it up in the first place.

"I won't tell."