The word(s) "doubt" appears 60 time(s) in 58 verse(s) in Quran in Muhammad Pickthal translation.

(31) (Pharaoh) said: Ye put your faith in him before I give you leave. Lo! he doubtless is your chief who taught you magic! But verily ye shall come to know. Verily I will cut off your hands and your feet alternately, and verily I will crucify you every one.

(32) Nay, but doth their knowledge reach to the Hereafter? Nay, for they are in doubt concerning it. Nay, for they cannot see it.

(33) And thou (O Muhammad) wast not a reader of any scripture before it, nor didst thou write it with thy right hand, for then might those have doubted, who follow falsehood.

(34) The revelation of the Scripture whereof there is no doubt is from the Lord of the Worlds.

(35) We verily gave Moses the Scripture; so be not ye in doubt of his receiving it; and We appointed it a guidance for the Children of Israel.

(36) And he had no warrant whatsoever against them, save that We would know him who believeth in the Hereafter from him who is in doubt thereof; and thy Lord (O Muhammad) taketh note of all things.

(37) And a gulf is set between them and that which they desire, as was done for people of their kind of old. Lo! they were in hopeless doubt.

(38) Hath the reminder been unto him (alone) among us? Nay, but they are in doubt concerning My reminder; nay but they have not yet tasted My doom.

(39) And verily Joseph brought you of old clear proofs, yet ye ceased not to be in doubt concerning what he brought you till, when he died, ye said: Allah will not send any messenger after him. Thus Allah deceiveth him who is a prodigal, a doubter.

(40) Lo! the Hour is surely coming, there is no doubt thereof; yet most of mankind believe not.