Going Home - S3-E11
Continuity mistake: When Peter Pan removes the enchanted black leather cuff from his arm, he uses his magic to transfer it to Mr. Gold's wrist. However, as he sends Mr. Gold flying across the room, there is a close-up of Pan's arm, where the cuff is back on his arm, next to the normal brown cuff that he usually wears. (00:21:20)
Going Home - S3-E11
Continuity mistake: In the Neverland flashback, when Hook offers Tinker Bell the rum bottle, the stopper (attached to the bottle) is hanging over the back of his hand. In the next shot, it is not. (00:09:55)
Answer: He knows who she is because he knows that the fairy tales are true. He was also shown to sneak out to go see Emma or someone else. Sometimes he succeeded, sometimes he didn't. This is how he knew to look for her despite his strict mother.