What is the expiation for one who swore falsely to justify a request for khulʿ, and what is the ruling on her desire to marry another after that?

A woman's request for divorce from her husband without a legitimate reason is a grave sin, based on the Prophet's (peace be upon him) saying: "Any woman who asks her husband for divorce without any [legitimate] cause, the scent of Paradise will be forbidden to her." The sin is further magnified if the reason is her desire for another man, and that man is also sinful for corrupting the woman against her husband.

The woman must fear Allah and stay away from this man. In such a case, her seeking khul' (divorce initiated by the wife) exposes her to divine punishment and deprivation from entering Paradise, based on the Prophet's (peace be upon him) saying: "Those who seek khul' are the hypocrites." However, if she needs to seek khul' for a legitimate reason, such as her intense dislike for her husband despite no fault on his part, then khul' is permissible for her, and she should return the mahr (dowry) he gave her.

As for swearing falsely against her husband that he used to insult and humiliate her, this is an oath that plunges its swearer into Hellfire (yameen ghamus), and it is one of the gravest major sins. Repentance, seeking forgiveness, and asking for the husband's pardon are obligatory. The majority of jurists hold that there is no expiation for it due to its magnitude.