I don’t know. I know that Rumple believes Belle to be dead but is there a way that Belle still has some memories of the past? This would be a great reason for Ragina to keep her locked up.
I can sort of buy Belle falling into Fairytale land through books like Henry did, after all that is what she lived through in her little town in The Disney version and the town thought she was crazy. Plus Ragina was quite mad about Henry having the book, ” What in the hell is this book I keep hearing about?!” Just imagine if you combined Henry and Belle. Keep all believers locked away in a mental ward or send them to a therapist.