"I'm trying to help."

He looks into Joker's eyes, to let him know he's sincere in this. Maybe he can't help Joker, but he can help Doll, or at least he hopes he can. It's not just about being nice; he wants to go beyond that.

"She showed me." He doesn't really elaborate on what she showed him, trusting Joker to understand. "She trusted me. So I can't leave it alone."