Stupid girl of course he'd believe you
That fairy really needs to learn human psychology. I don't blame her for being scared, it's scary to suddenly having these abilities and now you just have to get used to it with out disappointing the fairies. but if I were her I'd play it off cause like, I don't wanna die. But she was tired so she probably didn't get to actually know what to think about all this.
I don't like faries they're like tyrants and they don't give you even a vague warning, just nothing!