When he leaned away from her, Isobel looked up at him, her eyes searching his. She knew that her face had taken on a very different look from when he first kissed her and she was surprised it didn't send him running. After all, this was the proof of how much she had changed. The proof that she was no longer human. Not that he hadn't already known, but it was physical evidence, where before he had just been told.
"It's not like we haven't before," she pointed out before adding "yes, I'm sure." In fact, after the way he had been kissing her, she would end up very disappointed if it all stopped now.