Haha, I think she appreciated that comment about her lost youth being extremely valuable just a smidge too much, treating a kid she barely knew for five seconds like her son. Even if it's a way to get closer to her long lost lover.
@Glomoro - She probably respects him before loving him (the professor). When he exclaimed that he would be his only disciple, I believe that just led to more credence, thus, if her lover (professor) is treating him as though he was his own, she probably will too.
