The word(s) "doubt" appears 53 time(s) in 51 verse(s) in Quran in Saheeh International translation.

(1) This is the Book about which there is no doubt, a guidance for those conscious of Allah -

(2) And if you are in doubt about what We have sent down upon Our Servant [Muhammad], then produce a surah the like thereof and call upon your witnesses other than Allah, if you should be truthful.

(3) The truth is from your Lord, so never be among the doubters.

(4) O you who have believed, when you contract a debt for a specified term, write it down. And let a scribe write [it] between you in justice. Let no scribe refuse to write as Allah has taught him. So let him write and let the one who has the obligation dictate. And let him fear Allah, his Lord, and not leave anything out of it. But if the one who has the obligation is of limited understanding or weak or unable to dictate himself, then let his guardian dictate in justice. And bring to witness two witnesses from among your men. And if there are not two men [available], then a man and two women from those whom you accept as witnesses - so that if one of the women errs, then the other can remind her. And let not the witnesses refuse when they are called upon. And do not be [too] weary to write it, whether it is small or large, for its [specified] term. That is more just in the sight of Allah and stronger as evidence and more likely to prevent doubt between you, except when it is an immediate transaction which you conduct among yourselves. For [then] there is no blame upon you if you do not write it. And take witnesses when you conclude a contract. Let no scribe be harmed or any witness. For if you do so, indeed, it is [grave] disobedience in you. And fear Allah. And Allah teaches you. And Allah is Knowing of all things.

(5) Our Lord, surely You will gather the people for a Day about which there is no doubt. Indeed, Allah does not fail in His promise."

(6) So how will it be when We assemble them for a Day about which there is no doubt? And each soul will be compensated [in full for] what it earned, and they will not be wronged.

(7) The truth is from your Lord, so do not be among the doubters.

(8) Allah - there is no deity except Him. He will surely assemble you for [account on] the Day of Resurrection, about which there is no doubt. And who is more truthful than Allah in statement.

(9) And [for] their saying, "Indeed, we have killed the Messiah, Jesus, the son of Mary, the messenger of Allah." And they did not kill him, nor did they crucify him; but [another] was made to resemble him to them. And indeed, those who differ over it are in doubt about it. They have no knowledge of it except the following of assumption. And they did not kill him, for certain.

(10) O you who have believed, testimony [should be taken] among you when death approaches one of you at the time of bequest - [that of] two just men from among you or two others from outside if you are traveling through the land and the disaster of death should strike you. Detain them after the prayer and let them both swear by Allah if you doubt [their testimony, saying], "We will not exchange our oath for a price, even if he should be a near relative, and we will not withhold the testimony of Allah. Indeed, we would then be of the sinful."