The word(s) "doubt" appears 53 time(s) in 51 verse(s) in Quran in Muhammad Habib Shakir translation.

(31) And certainly We gave the Book to Musa, so be not in doubt concerning the receiving of it, and We made it a guide for the children of Israel.

(32) And he has no authority over them, but that We may distinguish him who believes in the hereafter from him who is in doubt concerning it; and your Lord is the Preserver of all things

(33) And a barrier shall be placed between them and that which they desire, as was done with the likes of them before: surely they are in a disquieting doubt.

(34) Has the reminder been revealed to him from among us? Nay! they are in doubt as to My reminder. Nay! they have not yet tasted My chastisement!

(35) And certainly Yusuf came to you before with clear arguments, but you ever remained in doubt as to what he brought; until when he died, you said: Allah will never raise an apostle after him. Thus does Allah cause him to err who is extravagant, a doubter

(36) No doubt that what you call me to has no title to be called to in this world, nor in the hereafter, and that our turning back is to Allah, and that the extravagant are the inmates of the fire;

(37) Most surely the hour is coming, there is no doubt therein, but most people do not believe.

(38) And certainly We gave the Book to Musa, but it has been differed about, and had not a word already gone forth from your Lord, judgment would certainly have been given between them; and most surely they are in a disquieting doubt about it.

(39) Now surely they are in doubt as to the meeting of their Lord; now surely He encompasses all things.

(40) And thus have We revealed to you an Arabic Quran, that you may warn the mother city and those around it, and that you may give warning of the day of gathering together wherein is no doubt; a party shall be in the garden and (another) party in the burning fire.