Does the marriage of a young man to a girl become invalid if she concealed her past mistakes from him, knowing full well that he would not have married her had he known about those mistakes?

The suitor should not ask his fiancée about her past. If her outward appearance is righteous, he should propose to her; otherwise, he should turn away. If he asks her, it is not permissible for her to tell him about the sins she has committed. Rather, she should repent and conceal her sins, and it is permissible for her to use allusive speech (ma'arid). Her not disclosing her past does not affect the validity of the marriage if its conditions are met.