I think Rumple is involved with this empty hearted curse somewhere. If Rumple isn’t planning to use this curse himself, then he must at least put the idea in Regina’s head, even if he makes her think it’s her idea all along. If Regina knew of this curse all along without Rumple’s assistance, why hasn’t she tried to use it on Henry before? She’s had the period of time between Tiny and this episode where she had fallen off her redemption wagon. If this curse was an option to get Henry to love her, why hasn’t Regina tried it already?