What is permissible and forbidden between a suitor and his fiancée? Is it permissible to propose to a non-Muslim girl who is not from the People of the Book with the intention of inviting her to Islam, provided that Islamic legal guidelines are adhered to and that he does not marry her if she does not embrace Islam?

The relationship between a suitor and his fiancée is like that with a foreign woman (a non-mahram). It is not permissible to propose to a disbelieving woman until she embraces Islam, because the proposal is a promise of marriage, and a promise that it is forbidden to fulfill is impermissible; for the means share the rulings of their ends. It is a condition that there be no legal impediment preventing immediate marriage to the woman, and that no other suitor has preceded him. Some Shafi'i jurists permitted proposing to a Zoroastrian woman (Majusiya) or similar if she converts to Islam, due to the encouragement therein for her to embrace Islam. It should be known that a man's invitation to a woman is never free from temptation (fitna); so if you wish to invite her [to Islam], seek out a Muslim sister to invite her. It is permissible for you to stipulate Islam as a condition for marrying her.