I agree. By the time Regina had hired the huntsman, Snow White clearly knew the reason for Regina’s hatred. In episode 8, she wrote a letter to Regina apologizing for keeping her from knowing true love. She must have found out about Daniel’s tragic end by then.
Dearest Step-Mother,
By the time you read this, I will be dead. I understand that you will never have love in you life because of me. So, it’s only fitting that I’ll be denied that same joy as well. For the sake of the kingdom, I hope my death satisfies your need for revenge, allowing you to rule my father’s subjects as they deserve, with compassion and a gentle hand. I know what you think you’re doing is vengeance, but I prefer to think of it as sacrifice, for the good of all. With that in mind, I welcome the end. I want you to take my last message to heart. I’m sorry, and I forgive you.
By the time she was older, SW clearly the real reason for Regina’s suffering was the secret she couldn’t keep at the age of 12. She’d pretty much realized that she was at fault for keeping Regina from true love. I think the reference in the pilot to Regina being jealous of her beauty was a quip. She really knew deep down that Regina had suffered because the king never loved Regina as she needed to be loved. King Leopold never considered Regina as fair as his first wife or his daughter. He never loved her the way that the stable boy, Daniel, had loved Regina.
"That’s how you know you’ve really got a home. When you leave it, there’s this feeling that you can’t shake. You just miss it." Neal Cassidy