I don’t really think Belle remembers anything about FTL. She wasn’t anyone with any special powers, so how would she be immune to the curse? Plus, having his true love not remember who he is would just be another punch in the gut to Rumple/Gold besides having to live with a bunch of people he can’t stand (Regina, the Fairies, etc.)
Depending on how Rumple/Gold handles himself around Belle would be a big factor in how she reacts to him. If he acts like a lovesick puppy around her, she may be just as creeped out as Emma was when she first met him. Wouldn’t you if some random stranger who looked 20 yrs older than you started drooling over you?
Even if she did somehow remember, we shouldn’t just think about if she would forgive him only for the events that took place FTL (Rumple casting her out of Dark Castle), but also about what’s already taken place in SB. How do you think she’s going to react when she finds out that Rumple/Gold nearly beat her own father to death for stealing something that she touched? Or when she finds out that he tricked Ashley/Cinderella into a deal that would cost her to give up her firstborn, and hired Emma to track her down to reclaim his “merchandise”? Or about any other shady deals he’s made during the past 28 years? At that point, Rumple/Gold would be lucky if she didn’t snatch his cane away and try to beat him with it!
As epic as their reunion would be, it’s probably not going to be a happy one. Even if it was, it’ll probably be the only happy moment they share for awhile. 😥