To what extent is a marriage contract valid and what are its resulting effects, and is it permissible to annul it based on deceit and fraud after the husband discovers that the wife is not a virgin as stated in the contract, and what is the ruling if the husband was aware of this beforehand?

If the marriage contract fulfills all the conditions (guardian's consent, witnesses, offer and acceptance), then it is valid, and the husband's knowledge or ignorance of the issue of virginity does not affect it. The woman or her guardian is not obliged to inform him of this unless requested. Therefore, the husband has no option for annulment.

However, if the husband stipulated virginity at the time of the contract, the marriage is also valid, but he has the option to annul or continue. If the annulment occurs before consummation, the woman is not entitled to any Mahr (dowry).