She files the information away in her mind for later use. It certainly sounds like something that needed to be investigated.

"Your partner is not helping your case."

She should have contacted her Enforcers just about now and warned them about this "darker" thing. But she wants to give Diarmuid some leeway, just as thanks for his child-rearing advice. Maybe she would regret this later, but for now, it was just an equivalent exchange.