The word(s) "doubted" appears 5 time(s) in 5 verse(s) in Quran in Abdullah Yusuf Ali translation.

(1) Undoubtedly Allah doth know what they conceal, and what they reveal: verily He loveth not the arrogant.

(2) And thou wast not (able) to recite a Book before this (Book came), nor art thou (able) to transcribe it with thy right hand: In that case, indeed, would the talkers of vanities have doubted.

(3) (David) said: "He has undoubtedly wronged thee in demanding thy (single) ewe to be added to his (flock of) ewes: truly many are the partners (in business) who wrong each other: Not so do those who believe and work deeds of righteousness, and how few are they?"... and David gathered that We had tried him: he asked forgiveness of his Lord, fell down, bowing (in prostration), and turned (to Allah in repentance).

(4) Only those are Believers who have believed in Allah and His Messenger, and have never since doubted, but have striven with their belongings and their persons in the Cause of Allah: Such are the sincere ones.

(5) (Those without) will call out, "Were we not with you?" (The others) will reply, "True! but ye led yourselves into temptation; ye looked forward (to our ruin); ye doubted (Allah's Promise); and (your false) desires deceived you; until there issued the Command of Allah. And the Deceiver deceived you in respect of Allah.