I don’t think that Snow did it on purpose. I just think that Regina believes she did. And i think that if Regina was ever to really listen to what Snow has to say about what happened. And Snow was to listen to what Regina says that maybe they could figure it out. I am not saying they are ever going to be friends, but maybe learn that it was all a horrible mistake and was not intentional. And i think it is a great theory that maybe Cora did do something to Snow’s mother, i also thought that it was going to be Regina who killed Snow’s mother, but maybe it was Cora, hopping to get her daughter to be queen.