@osqmu, it didn't happen suddenly, it has been building up since she was born. For all her years she have been shunned, feared, ignored by those that where supposed to be her closest family, and the rest of the kingdom. Such a treatment like that for so long will harm the person alot, and...
It would be nice if those two wheren't the main couple, but we all know how this will go. She will end up with black hair playboy in the end, which is a huge minus in my book.