Can a girl be mentioned in the marriage contract as a virgin, knowing that she is not?

If the girl is pleasing in terms of religion and character, then propose to her. Avoid explicitly stating that she is "a virgin" because it is the guardian who is concerned with mentioning that. If you are compelled to state it, use dissimulation (tawriyah), such as saying "a virgin" intending that she is considered as such by her family, or that she was a virgin before her marriage, in order to provide cover for her and her family.