I posted under Rumple/Gold character analysis that I thought Rumples hates Regina because he was not able to get her after Cora guessed his name. After hearing other’s thoughts though I agree that Regina doesn’t seem like the first born.
Regina seems like the unfavored second born who’s mother gave all her love to the older sibling. In this case Cora no longer has her first-born and resents Regina even more for that.
The way that Cora and Regina are able to pull hearts out of people’s chests is way to coincidental to not be related to the Queen of Hearts in some way.
I know people think Cora is not the Queen of Hearts, but I really do believe she is. For one, the way her relationship with her husband Henry was portrayed, proved to me she would have no problem capturing him in Wonderland and holding him captive in a box. The obvious close relationship Regina and Henry share that sharply contrasts with Cora and Regina’s relationship also pointed to future events unfolding as we saw them in ‘Hat Trick.’
Side Note – Cora has the seemingly same hairstyle as the Queen of Hearts . . .