The word(s) "certain" appears 144 time(s) in 135 verse(s) in Quran in Abdullah Yusuf Ali translation.

(51) What is with you must vanish: what is with Allah will endure. And We will certainly bestow, on those who patiently persevere, their reward according to the best of their actions.

(52) Say: If there had been (other) gods with Him, as they say,- behold, they would certainly have sought out a way to the Lord of the Throne!

(53) And their purpose was to tempt thee away from that which We had revealed unto thee, to substitute in our name something quite different; (in that case), behold! they would certainly have made thee (their) friend!

(54) Say, "If there were settled, on earth, angels walking about in peace and quiet, We should certainly have sent them down from the heavens an angel for a messenger."

(55) Thou wouldst have deemed them awake, whilst they were asleep, and We turned them on their right and on their left sides: their dog stretching forth his two fore-legs on the threshold: if thou hadst come up on to them, thou wouldst have certainly turned back from them in flight, and wouldst certainly have been filled with terror of them.

(56) "As for the boat, it belonged to certain men in dire want: they plied on the water: I but wished to render it unserviceable, for there was after them a certain king who seized on every boat by force.

(57) Then shall We certainly drag out from every sect all those who were worst in obstinate rebellion against (Allah) Most Gracious.

(58) And certainly We know best those who are most worthy of being burned therein.

(59) Hast thou then seen the (sort of) man who rejects Our Signs, yet says: "I shall certainly be given wealth and children?"

(60) They said: "These two are certainly (expert) magicians: their object is to drive you out from your land with their magic, and to do away with your most cherished institutions.