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

(121) That He (Allah) may make what is thrown in by Shaitan (Satan) a trial for those in whose hearts is a disease (of hypocrisy and disbelief) and whose hearts are hardened. And certainly, the Zalimun (polytheists and wrong-doers) are in an opposition far-off (from the truth against Allah's Messenger and the believers).

(122) Invoke not loudly this day! certainly you shall not be helped by Us.

(123) And certainly, you (O Muhammad صلى الله عليه وسلم) call them to the Straight Path (true religion - Islamic Monotheism).

(124) Allah has promised those among you who believe and do righteous good deeds, that He will certainly grant them succession to (the present rulers) in the land, as He granted it to those before them, and that He will grant them the authority to practise their religion which He has chosen for them (i.e. Islam). And He will surely give them in exchange a safe security after their fear (provided) they (believers) worship Me and do not associate anything (in worship) with Me. But whoever disbelieves after this, they are the Fasiqun (rebellious, disobedient to Allah).

(125) certainly, to Allah belongs all that is in the heavens and the earth. Surely, He knows your condition and (He knows) the Day when they will be brought back to Him, then He will inform them of what they did. And Allah is All-Knower of everything.

(126) [Musa (Moses)] said: "The Lord of the heavens and the earth, and all that is between them, if you seek to be convinced with certainty."

(127) [Fir'aun (Pharaoh)] said: "If you choose an ilah (god) other than me, I will certainly put you among the prisoners."

(128) So they threw their ropes and their sticks, and said: "By the might of Fir'aun (Pharaoh), it is we who will certainly win!"

(129) Those who perform As-Salat (Iqamat-as-Salat) and give Zakat and they believe with certainty in the Hereafter (resurrection, recompense of their good and bad deeds, Paradise and Hell).

(130) One with whom was knowledge of the Scripture said: "I will bring it to you within the twinkling of an eye!" Then when he [Sulaiman (Solomon)] saw it placed before him, he said: "This is by the Grace of my Lord - to test me whether I am grateful or ungrateful! And whoever is grateful, truly, his gratitude is for (the good of) his ownself; and whoever is ungrateful, (he is ungrateful only for the loss of his ownself). certainly my Lord is Rich (Free of all needs), Bountiful."