Rumple’s request of Emma is probably much more simplier than we think. Emma is a Princess and Charming and Snow’s heir. She has the potential to be very powerful or is already. Rumple has done dubious things to others to get what he wants and to accomplish what he needs to do. Perhaps his request of Princess Emma is just simply to be forgiven for even pardoned for any wrongdoing. Rumple’s MO is that the ends justifies the means……what if the ends is that everybody who is still alive by the very end has their happy ending but getting to that end more people either gets hurt or even killed; only a royal can issue such a pardon for these crimes and that is Emma.