Is it necessary to break off an engagement to a girl who has been subjected to harassment, knowing that she is of good character and religious, and has preserved her virginity?

If a girl is religious and of good character, then the Sharīʿah encourages marrying someone like her. The harassment the girl experienced is not a legitimate impediment to marriage, especially if she was not the cause of it. And if she was the cause, it is sufficient for her to repent to Allah. She is not obligated to inform you about the harassment, and a virginity test is impermissible except when absolutely necessary. The loss of the hymen does not necessarily indicate engaging in indecency, as it can be lost due to other causes besides intercourse.