Regina having her heart was a huge hindrance to that [Regina and Robin] relationship developing. Regina’s heart has known so much loss, pain, and darkness. Removing it has allowed her to move on from the pain she has carried in her heart since Daniel died. It allowed her to feel with her soul instead, and we know from Tinker Bell’s words that Robin is Regina’s soul mate.
NOT HAVING HER HEART seemed to help Regina’s SOUL find its mate without the fear she still held in her heart about finding a second chance at happiness.”