Katara was correct in her thinking. Nodding wasn't enough of an answer for someone like Toph. You know, because she couldn't exactly see the nodding part. "Vampires and demons." That sounded odd to her, but her confidence in her earthbending skills kicked in. She could take care of herself if the moment called for it, whether it be a vampire or a demon.
Judging from the other girl's silence, it was easy to tell that she was avoiding the question. Once again, she was right in thinking that Toph wouldn't stand for it. She liked her questions answered, thank you very much. So she was completely prepared to listen, because an explanation as to why Katara had referred to their long time enemy as if talking about a friend was something she definitely needed to hear.
But this explanation confused her a bit. Prince Zuko, the same Zuko who had been hunting the Avatar and had been their opponent a number of times had suddenly had a change of heart? It didn't exactly add up in Toph's mind. Mostly because she still had a whole lot of dislike for him. It was just a little hard to believe that he turned on the Fire Nation and wanted to teach Aang firebending.
"...I personally find that a little hard to believe." The petite earthbender crossed her arms over her chest. "What are the chances that he's had a genuine change of heart? Unless something happened when he went back to the Fire Nation." But, if Katara believed him, it had to be at least somewhat true, right?