The word(s) "unbelieving" appears 3 time(s) in 2 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) Do not marry unbelieving women (idolaters), until they believe: A slave woman who believes is better than an unbelieving woman, even though she allures you. Nor marry (your girls) to unbelievers until they believe: A man slave who believes is better than an unbeliever, even though he allures you. Unbelievers do (but) beckon you to the Fire. But Allah beckons by His Grace to the Garden (of bliss) and forgiveness, and makes His Signs clear to mankind: That they may celebrate His praise.

(2) O ye who believe! When there come to you believing women refugees, examine (and test) them: Allah knows best as to their Faith: if ye ascertain that they are Believers, then send them not back to the Unbelievers. They are not lawful (wives) for the Unbelievers, nor are the (Unbelievers) lawful (husbands) for them. But pay the Unbelievers what they have spent (on their dower), and there will be no blame on you if ye marry them on payment of their dower to them. But hold not to the guardianship of unbelieving women: ask for what ye have spent on their dowers, and let the (Unbelievers) ask for what they have spent (on the dowers of women who come over to you). Such is the command of Allah: He judges (with justice) between you. And Allah is Full of Knowledge and Wisdom.