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

(51) And indeed We gave Musa (Moses) the Scripture [the Taurat (Torah)] So be not you in doubt of meeting him [i.e. when you met Musa (Moses) during the night of Al-Isra' and Al-Mi'raj over the heavens]. And We made it [the Taurat (Torah)] a guide to the Children of Israel.

(52) When they came upon you from above you and from below you, and when the eyes grew wild and the hearts reached to the throats, and you were harbouring doubts about Allah.

(53) And when the hypocrites and those in whose hearts is a disease (of doubts) said: "Allah and His Messenger (صلى الله عليه وسلم) promised us nothing but delusion!"

(54) And he (Iblis - Satan) had no authority over them, - except that We might test him who believes in the Hereafter from him who is in doubt about it. And your Lord is a Hafiz (Watchful) over everything. (All-Knower of everything i.e. He keeps record of every person as regards deeds, and then He will reward them accordingly).

(55) And a barrier will be set between them and that which they desire [i.e. At-Taubah (turning to Allah in repentance) and the accepting of Faith], as was done in the past with the people of their kind. Verily, they have been in grave doubt.

(56) "Has the Reminder been sent down to him (alone) from among us?" Nay, but they are in doubt about My Reminder (this Qur'an)! Nay, but they have not tasted (My) Torment!

(57) And indeed Yusuf (Joseph) did come to you, in times gone by, with clear signs, but you ceased not to doubt in that which he did bring to you: till when he died you said: "No Messenger will Allah send after him." Thus Allah leaves astray him who is a Musrif (a polytheist, an oppressor, a criminal, sinner who commit great sins) and a Murtab (one who doubts Allah's Warning and His Oneness).

(58) "No doubt you call me to (worship) one who cannot grant (me) my request (or respond to my invocation) in this world or in the Hereafter. And our return will be to Allah, and Al-Musrifun (i.e. polytheists and arrogants, those who commit great sins, the transgressors of Allah's set limits): they shall be the dwellers of the Fire!

(59) Verily, the Hour (Day of Judgement) is surely coming, there is no doubt about it, yet most men believe not.

(60) And indeed We gave Musa (Moses) the Scripture, but dispute arose therein. And had it not been for a Word that went forth before from your Lord, (the torment would have overtaken them) and the matter would have been settled between them. But truly, they are in grave doubt thereto (i.e. about the Qur'an). [Tafsir Al-Qurtubi].