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

(21) When you are greeted with a greeting, greet in return with what is better than it, or (at least) return it equally. certainly, Allah is Ever a Careful Account Taker of all things.

(22) And seek the Forgiveness of Allah, certainly, Allah is Ever Oft-Forgiving, Most Merciful.

(23) Had not the Grace of Allah and His Mercy been upon you (O Muhammad صلى الله عليه وسلم), a party of them would certainly have made a decision to mislead you, but (in fact) they mislead none except their own selves, and no harm can they do to you in the least. Allah has sent down to you the Book (The Qur'an), and Al-Hikmah (Islamic laws, knowledge of legal and illegal things i.e. the Prophet's Sunnah - legal ways), and taught you that which you knew not. And Ever Great is the Grace of Allah unto you (O Muhammad صلى الله عليه وسلم).

(24) Verily, I will mislead them, and surely, I will arouse in them false desires; and certainly, I will order them to slit the ears of cattle, and indeed I will order them to change the nature created by Allah." And whoever takes Shaitan (Satan) as a Wali (protector or helper) instead of Allah, has surely suffered a manifest loss.

(25) And it has already been revealed to you in the Book (this Qur'an) that when you hear the Verses of Allah being denied and mocked at, then sit not with them, until they engage in a talk other than that; (but if you stayed with them) certainly in that case you would be like them. Surely, Allah will collect the hypocrites and disbelievers all together in Hell.

(26) And because of their saying (in boast), "We killed Messiah 'Îsa (Jesus), son of Maryam (Mary), the Messenger of Allah," - but they killed him not, nor crucified him, but it appeared so to them [the resemblance of 'Îsa (Jesus) was put over another man (and they killed that man)], and those who differ therein are full of doubts. They have no (certain) knowledge, they follow nothing but conjecture. For surely; they killed him not [i.e. 'Îsa (Jesus), son of Maryam (Mary) عليهما السلام]:

(27) For the wrong-doing of the Jews, We made unlawful for them certain good foods which had been lawful for them - and for their hindering many from Allah's Way;

(28) Verily, those who disbelieve [by concealing the truth about Prophet Muhammad صلى الله عليه وسلم and his message of true Islamic Monotheism written in the Taurat (Torah) and the Injeel (Gospel) with them] and prevent (mankind) from the Path of Allah (Islamic Monotheism); they have certainly strayed far away. (Tafsir Al-Qurtubi).

(29) O mankind! Verily, there has come to you the Messenger (Muhammad صلى الله عليه وسلم) with the truth from your Lord. So believe in him, it is better for you. But if you disbelieve, then certainly to Allah belongs all that is in the heavens and the earth. And Allah is Ever All-Knowing, All-Wise.

(30) O you who believe! Allah will certainly make a trial of you with something in (the matter of) the game that is well within the reach of your hands and your lances, that Allah may test him who fears Him unseen. Then whoever transgresses thereafter, for him there is a painful torment.