Crowley nods, trying to listen more than talk, but understands that maybe his own honesty may spark some from Aziraphale in return. He doesn't like the idea of the angel being terrified or hurt, but what can he really do outside of hopefully persuade him to open up.

"To some, our existence is difficult to believe." he replies, cautiously. "But there's no point contemplating how realistic it is, it's happening. Terrifying or not.