The word(s) "certain" appears 184 time(s) in 178 verse(s) in Quran in Mohsin Khan translation.

(151) Nay! They say: "We found our fathers following a certain way and religion, and we guide ourselves by their footsteps."

(152) And similarly, We sent not a warner before you (O Muhammad صلى الله عليه و سلم) to any town (people) but the luxurious ones among them said: "We found our fathers following a certain way and religion, and we will indeed follow their footsteps."

(153) The Lord of the heavens and the earth and all that is between them, if you (but) have a faith with certainty.

(154) certainly, We have made this (Qur'an) easy in your tongue, in order that they may remember.

(155) And in your creation, and what He scattered (through the earth) of moving (living) creatures are signs for people who have Faith with certainty.

(156) This (Qur'an) is a clear insight and evidence for mankind, and a guidance and a mercy for people who have Faith with certainty.

(157) So, when you meet (in fight - Jihad in Allah's Cause) those who disbelieve, smite (their) necks till when you have killed and wounded many of them, then bind a bond firmly (on them, i.e. take them as captives). Thereafter (is the time) either for generosity (i.e. free them without ransom), or ransom (according to what benefits Islam), until the war lays down its burden. Thus [you are ordered by Allah to continue in carrying out Jihad against the disbelievers till they embrace Islam and are saved from the punishment in the Hell-fire or at least come under your protection], but if it had been Allah's Will, He Himself could certainly have punished them (without you). But (He lets you fight) in order to test some of you with others. But those who are killed in the Way of Allah, He will never let their deeds be lost.

(158) certainly Allah will admit those who believe (in the Oneness of Allah - Islamic Monotheism) and do righteous good deeds, to Gardens under which rivers flow (Paradise); while those who disbelieve enjoy themselves and eat as cattle eat; and the Fire will be their abode.

(159) And if those who disbelieve fight against you, they certainly would have turned their backs; then they would have found neither a Wali (protector, guardian) nor a helper.

(160) Indeed Allah shall fulfil the true vision which He showed to His Messenger (صلى الله عليه وسلم) [i.e. the Prophet صلى الله عليه وسلم saw a dream that he has entered Makkah along with his Companions, having their (head) hair shaved and cut short] in very truth. certainly, you shall enter Al-Masjid-al-Haram, if Allah wills, secure, (some) having your heads shaved, and (some) having your head hair cut short, having no fear. He knew what you knew not, and He granted besides that a near victory.