I'm confused; the title suggests she will learn magic, but right now she's a seamstress and the description indicates she will be pursued by the crown prince of the country she has fled to. Well, I'll at least see where this goes.
@johnpoop2529
If you trust the description, she is apparently childhood friends with the crown prince of the country she has fled to. So she knows the person she is calling an idiot pretty boy prince. Of course, it is possible she doesn't actually remember him and is just making a generic statement. In any case, it is certainly arrogant.
@petitehime
It was a thought she kept for herself. I wouldn't say that a person is strong when they make an ambiguous statement about one being unworthy of the other to make others think that she is demeaning herself when internally she is protecting her pride by thinking that it is the other party that is unworthy and likely additionally looking down on others who can't tell that she is being arrogant. It's quite clear from her other thoughts about the seamstress' chatter that she thinks she is much wiser than them. She's also making another internal statement about how marriage between different classes will not be happy, except her father had a lover which I expect wasn't nobility and both the lover and daughter are currently in a better situation than herself. So she's clearly a bit stupid and that would explain how she got herself banished - she either took thoughtless actions towards her stepsister or she was framed and she should have seen it coming and taken preventive measures. Right now she is destitute so she clearly didn't have any fallback plan. And does her mother not have a family who would have been enraged about their daughter being treated the way she was by having a lover come live in the main house?