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

(161) certainly, you have different ideas (about Muhammad صلى الله عليه وسلم and the Qur'an).

(162) And on the earth are signs for those who have Faith with certainty.

(163) Verily, this! This is an absolute Truth with certainty.

(164) And had it not been that Allah had decreed exile for them, He would certainly have punished them in this world; and in the Hereafter theirs shall be the torment of the Fire.

(165) certainly, there has been in them an excellent example for you to follow - for those who look forward to (the Meeting with) Allah and the Last Day. And whosoever turns away, then verily, Allah is Rich (Free of all needs), Worthy of all Praise.

(166) O you who believe! When believing women come to you as emigrants, examine them; Allah knows best as to their Faith, then if you ascertain that they are true believers send them not back to the disbelievers. They are not lawful (wives) for the disbelievers nor are the disbelievers lawful (husbands) for them. But give them (the disbelievers) that (amount of money) which they have spent [as their Mahr] to them. And there will be no sin on you to marry them if you have paid their Mahr to them. Likewise hold not the disbelieving women as wives, and ask for (the return of) that which you have spent (as Mahr ) and let them (the disbelievers) ask back for that which they have spent. That is the Judgement of Allah, He judges between you. And Allah is All-Knowing, All-Wise.

(167) And (remember) when Musa (Moses) said to his people: "O my people! Why do you annoy me while you know certainly that I am the Messenger of Allah to you? So when they turned away (from the Path of Allah), Allah turned their hearts away (from the Right Path). And Allah guides not the people who are Fasiqun (the rebellious, the disobedient to Allah).

(168) The disbelievers pretend that they will never be resurrected (for the Account). Say (O Muhammad صلى الله عليه وسلم): Yes! By my Lord, you will certainly be resurrected, then you will be informed of (and recompensed for) what you did; and that is easy for Allah.

(169) No calamity befalls, but by the Leave [i.e. Decision and Qadar (Divine Preordainments)] of Allah, and whosoever believes in Allah, He guides his heart [to the true Faith with certainty, i.e. what has befallen him was already written for him by Allah from the Qadar (Divine Preordainments)]. And Allah is the All-Knower of everything.

(170) And then We certainly would have cut off his life artery (aorta),