"I was listening. I'm sorry, I just was... listening very closely," he explained. That was the truth.
Another "truth": L found that he was absolutely incapable of telling a lie when he was near Blythe.
"I understand fine," he said earnestly. "I'd like to borrow them all... I read so fast, you'd have them back within a night or two, at the latest." He crept backward an inch when she leaned forward approximately the same amount. The last thing he needed was for this situation to get so charged that he lost control of himself.