The word(s) "doubted" appears 2 time(s) in 2 verse(s) in Quran in Mohsin Khan translation.

(1) Neither did you (O Muhammad صلى الله عليه وسلم) read any book before it (this Qur'an), nor did you write any book (whatsoever) with your right hand. In that case, indeed, the followers of falsehood might have doubted.

(2) (The hypocrites) will call the believers: "Were we not with you?" The believers will reply: "Yes! But you led yourselves into temptations, you looked forward for our destruction; you doubted (in Faith) and you were deceived by false desires, till the Command of Allah came to pass. And the chief deceiver (Satan) deceived you in respect of Allah."