I really think that Emma is already starting to wonder if the stories are real. In Hat Trick she looked through the book for the Hatter’s story and in Stable Boy she was again looking through the book and while part of her still thinks it is nuts, the other part of her is trying to find evidence. There was the evidence with the keys and the fact that the story Jefferson told her was true and he had the scar and he disappeared after he fell out the window. And Emma certainly isn’t all in with her belief, but the fact that she is looking through the book is a huge step.
And i think that if she sees something like someone do something or hears someone say something that maybe she could get there.