Katherine understood a little about why he did it, but obviously this was something that was dangerous to put on someone. Sure Pavel is feeling better, but it was at Adri's expense.
She was searching for something to say to try and make a good point without seeming as though she were being too invasive when Adri said something else. It wasn't so much the what she said, but more how she said it. "What's wrong?" she asked. She wasn't too versed on fairies in general much less particular offsets that need sex to live, so there wasn't really any conclusion the young girl could have gleamed from Adri's apparent revelation.