The word(s) "doubt" appears 83 time(s) in 77 verse(s) in Quran in Mohsin Khan translation.

(11) O you who believe! When death approaches any of you, and you make a bequest, (then take) the testimony of two just men of your own folk or two others from outside, while you are travelling through the land and death befalls on you. Detain them both after As-Salat (the prayer), (then) if you are in doubt (about their truthfulness), let them both swear by Allah (saying): "We wish not for any worldly gain in this, even though he (the beneficiary) be our near relative. We shall not hide Testimony of Allah, for then indeed we should be of the sinful."

(12) He it is Who has created you from clay, and then has decreed a (stated) term (for you to die). And there is with Him another determined term (for you to be resurrected), yet you doubt (in the Resurrection).

(13) Say (O Muhammad صلى الله عليه وسلم): "To whom belongs all that is in the heavens and the earth?" Say: "To Allah. He has prescribed Mercy for Himself. Indeed He will gather you together on the Day of Resurrection, about which there is no doubt. Those who have lost themselves will not believe [in Allah as being the only Ilah (God), and Muhammad صلى الله عليه وسلم as being one of His Messengers, and in Resurrection].

(14) [Say (O Muhammad صلى الله عليه وسلم)] "Shall I seek a judge other than Allah while it is He Who has sent down unto you the Book (the Qur'an), explained in detail." Those unto whom We gave the Scripture [the Taurat (Torah) and the Injeel (Gospel)] know that it is revealed from your Lord in truth. So be not you of those who doubt.

(15) It is only those who believe not in Allah and the Last Day and whose hearts are in doubt that ask your leave (to be exempted from Jihad). So in their doubts they waver.

(16) The building which they built will never cease to be a cause of hypocrisy and doubt in their hearts unless their hearts are cut to pieces. (i.e. till they die). And Allah is All-Knowing, All-Wise.

(17) But as for those in whose hearts is a disease (of doubt, disbelief and hypocrisy), it will add suspicion and doubt to their suspicion, disbelief and doubt; and they die while they are disbelievers.

(18) And this Qur'an is not such as could ever be produced by other than Allah (Lord of the heavens and the earth), but it is a confirmation of (the revelation) which was before it [i.e. the Taurat (Torah), and the Injeel (Gospel)], and a full explanation of the Book (i.e. laws, decreed for mankind) - wherein there is no doubt - from the Lord of the 'Alamin (mankind, jinn, and all that exists).

(19) No doubt, surely, all that is in the heavens and the earth belongs to Allah. No doubt, surely, Allah's Promise is true. But most of them know not.

(20) O mankind! There has come to you a good advice from your Lord (i.e. the Qur'an, enjoining all that is good and forbidding all that is evil), and a healing for that (disease of ignorance, doubt, hypocrisy and differences) which is in your breasts, - a guidance and a mercy (explaining lawful and unlawful things) for the believers.