I don’t get how “rebooting” at the series end would allow Emma to grow up from birth with Snow White and Price Charming as parents in FTL. I doubt breaking the curse would somehow magically restart time and change it. That just doesn’t make any sense.
In all likelihood, I agree with Phee that Regina has suspected ever since episode 2 who Emma really is. She accused Mr. Gold of intentionally bringing Henry to her so that Emma would come to SB. Also, Mr. Gold said that Regina probably knew exactly who Emma really is. I think that Regina has sort of hoped that Emma would continue to disbelieve in the curse. The fact that Regina believes Mr. Gold when he says that killing Emma would break the dark curse is the real reason Emma is still alive. Regina wants to keep her power and curse in tact, which is why she hasn’t killed Emma. Yet, she sees that the curse has been weakening ever since Emma showed up in SB. We saw in episode 21 that Regina when to great lengths to retrieve the magic apple to put Emma into a deep sleep rather than kill her.
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy