Ruby
I can't comment on what it's like to lose a true love, since I've never had one to lose. But the whole reason that happened was because she tore out my heart, made me her prisoner and turned me into her sex slave before she killed me.
What I don't understand is she tried to kill Snow a lot. Repeatedly. And now she's claiming some sort of motherly concern? How does that even work? Regina is the reason Snow lost her child, the reason Emma had to grow up alone in the world all those years.