I had no problem with the reunion–I really loved both scenes with them. It was a surprise to see them both together, since it was a popular thought and rumour that the two of them would reunite in season 2. I had also heard that Belle was going to die, so it was a relief to see that both sources were wrong.
That said, I never once thought that Rumpelstiltskin chose magic over Belle in the last scene. First, this was planned. He was always going to go to the well and drop the potion–the scene before Belle comes into the shop is proof. Second, he is going to need magic. Regina is not the only one in trouble–once everyone finds out that he made the curse, they will be out for him, and without magic, he’ll die. Also, he’s probably still looking for Bae–I doubt he has given up on him, and he will most likely need magic to find him. He let both Bae and Belle down with his choices, and so I think he has learned his lesson, and he has no intention of using his powers as he had before.
The first time Mr. Gold sees Belle is clear proof that he still loves her. He can’t believe it’s her–he has to touch her shoulder to believe. It makes me think that he must have seen her before–a dream, a figment of his imagination. And when he asks, “She did this to you?” it just foreshadows that Regina is in trouble, and I think it also shows his guilt that he easily took Regina’s word. He was willing to trust her word on the matter and–as far as we can see–never looked for her, and because of that, Belle had been locked away for who knows how long. Then he says he will protect her, and that shows he does not want to repeat the mistakes he has made before. We already got that briefly when he thought August was Bae. When he says that Belle will remember, he sounds almost frightened, as though he fears what her reaction will be when she recalls how he had treated her.
We don’t what happens afterwards–we can guess that he quickly leaves the shop (he seemed to be in a real hurry) and takes her with him. And then when Belle remembers, he actually looks truly frightened, and that shows that he has been living in regret. He looks afraid of her reaction, if she will reject him, yell at him, or walk away from him. Yet she says she loves him, and the pure relief and love is present in both his expression and voice. He finally admits that he loves her.