The interaction between the two was definitely enough to keep her attention. This was all leading somewhere. "He doesn't know," she said stating the obvious. Who she was speaking to was up in the air. She could have easily been telling Red Hood that Damian didn't know who he was dealing with, but the truth was, she was saying that Red Hood didn't know who Damian was.
Her eyes hadn't left the masked man since he'd arrived. Even if they didn't know each other, she obviously trusted the child more than she trusted him.