Board Thread:Character Discussion/@comment-261373-20140515193604/@comment-261373-20140520164848

Actually, Henry's book didn't clearly show them as Hook and Emma. Mary Margaret was surprised at the end when Emma reveal to her that Princess Leia was Emma. Emma pointed to a  picture of Princess Leia in the book to them (Mary Margaret, David and Henry) and reveal that  was actually her. Mary Margaret was surprise and ask for reconfirming "So you were Princess Leia?" and Emma  nodded reconfirming.

Mary Margaret then went on to later say  "See, now you're part of the stories." This is to calm Emma's disappointment earlier. Earlier in the show, Emma wanted to leave Storybrooke because she felt she didn't belong. She didn't feel she belong because she was not featured in the book, didn't get to live the Enchanted Forest life, didn't get a chance to be a Princess, etc. Time travelling allow to do that and still have a normal life/Land Without Magic. The flashback to scenes show this

Normal Life/Land Without Magic: Emma was still a thief who met Neal.

Enchanted Forest: While we the viewers  know she's Emma pretending to be Princess Leia (You guys are right in saying that Princess Leia was a fake name she took, BUT) and here's a big BUT, for all intent and purpose, all the characters (except Rumplestilskin) (including her mom and dad until she reveal it to them later on) see her as Princesss Leia.

So in a way, briefly in many characters eyes, Emma and Princess Leia were two different people, until it was reveal they're one of the same. Emma inadvertently alter history to allow herself to be a part of history.