Regina should’ve been firm in saying no to her mom and dad for the marriage
Now, looking back on Once Upon a Time, Regina should’ve been firmer on saying no to the marriage and introduced them to Daniel.
If you are firm in your resolve to not do something and you say what you’re going to do while actually doing it, people tend to back off.
EDIT: I know that even if she is firm, her mom wouldn’t have backed off. But, at least, she would have the strength to stand up for herself and live life on her own terms.