Why is it stipulated for a non-Muslim to convert to Islam in order to marry a Muslim woman?

The reason for prohibiting the marriage of a non-Muslim man to a Muslim woman is the ruling and law of Allah Almighty, as He says: "Then do not return them to the disbelievers; neither are they lawful for them, nor are they lawful for them [as husbands]," and "And do not marry [your women] to idolaters until they believe."

The wisdom behind this prohibition is the fear of the Muslim woman falling into disbelief, because the husband invites her to his religion, and women generally follow men and imitate them in religion. The Quran alludes to this by saying: "Those invite to the Fire," because the disbeliever's invitation to the Muslim woman to his religion is an invitation to disbelief, and disbelief necessitates the Fire. Thus, this marriage would be a cause inviting to what is forbidden.