“If you can bottle love you can do anything.” Even though Rumple is the most powerful man in the world I think two things have eluded him so far – love and life. But he said “If you can bottle love you can do anything.” I think he wanted to find a way to bring Bae and Belle back, thinking they are both dead and realized that if he could find a way to bottle love then he could find a way to bring the dead back. But I think that bringing the dead back would somehow require the Dark Curse so he needed to have the product of love (Emma) in order to destroy the Dark Curse. When he added James’ hair to Snow’s in the bottle it looked like a DNA helix – which would have been Emma’s DNA.