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

(61) (Pharaoh) said: "Believe ye in Him before I give you permission? Surely this must be your leader, who has taught you magic! be sure I will cut off your hands and feet on opposite sides, and I will have you crucified on trunks of palm-trees: so shall ye know for certain, which of us can give the more severe and the more lasting punishment!"

(62) (Moses) said: "Get thee gone! but thy (punishment) in this life will be that thou wilt say, 'touch me not'; and moreover (for a future penalty) thou hast a promise that will not fail: Now look at thy god, of whom thou hast become a devoted worshipper: We will certainly (melt) it in a blazing fire and scatter it broadcast in the sea!"

(63) And if We had inflicted on them a penalty before this, they would have said: "Our Lord! If only Thou hadst sent us a messenger, we should certainly have followed Thy Signs before we were humbled and put to shame."

(64) And remember David and Solomon, when they gave judgment in the matter of the field into which the sheep of certain people had strayed by night: We did witness their judgment.

(65) (They are) those who have been expelled from their homes in defiance of right,- (for no cause) except that they say, "our Lord is Allah". Did not Allah check one set of people by means of another, there would surely have been pulled down monasteries, churches, synagogues, and mosques, in which the name of Allah is commemorated in abundant measure. Allah will certainly aid those who aid his (cause);- for verily Allah is full of Strength, Exalted in Might, (able to enforce His Will).

(66) And We send down water from the sky according to (due) measure, and We cause it to soak in the soil; and We certainly are able to drain it off (with ease).

(67) "If ye obey a man like yourselves, behold, it is certain ye will be lost.

(68) (It will be said): "Groan not in supplication this day: for ye shall certainly not be helped by Us.

(69) And We are certainly able to show thee (in fulfilment) that against which they are warned.

(70) Let those who find not the wherewithal for marriage keep themselves chaste, until Allah gives them means out of His grace. And if any of your slaves ask for a deed in writing (to enable them to earn their freedom for a certain sum), give them such a deed if ye know any good in them: yea, give them something yourselves out of the means which Allah has given to you. But force not your maids to prostitution when they desire chastity, in order that ye may make a gain in the goods of this life. But if anyone compels them, yet, after such compulsion, is Allah, Oft-Forgiving, Most Merciful (to them),