The word(s) "hearts" appears 132 time(s) in 121 verse(s) in Quran in Mohsin Khan translation.

(11) And hold fast, all of you together, to the Rope of Allah (i.e. this Qur'an), and be not divided among yourselves , and remember Allah's Favour on you, for you were enemies one to another but He joined your hearts together, so that, by His Grace, you became brethren (in Islamic Faith), and you were on the brink of a pit of Fire, and He saved you from it. Thus Allah makes His Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.,) clear to you, that you may be guided.

(12) Allah made it not but as a message of good news for you and as an assurance to your hearts. And there is no victory except from Allah, the All-Mighty, the All-Wise.

(13) We shall cast terror into the hearts of those who disbelieve, because they joined others in worship with Allah, for which He had sent no authority; their abode will be the Fire and how evil is the abode of the Zalimun (polytheists and wrong-doers).

(14) Then after the distress, He sent down security for you. Slumber overtook a party of you, while another party was thinking about themselves (as how to save their ownselves, ignoring the others and the Prophet صلى الله عليه وسلم) and thought wrongly of Allah - the thought of ignorance. They said, "Have we any part in the affair?" Say (O Muhammad صلى الله عليه وسلم): "Indeed the affair belongs wholly to Allah." They hide within themselves what they dare not reveal to you, saying: "If we had anything to do with the affair, none of us would have been killed here." Say: "Even if you had remained in your homes, those for whom death was decreed would certainly have gone forth to the place of their death," but that Allah might test what is in your breasts; and to purify that which was in your hearts (sins), and Allah is All-Knower of what is in (your) breasts.

(15) O you who believe! Be not like those who disbelieve (hypocrites) and who say to their brethren when they travel through the earth or go out to fight: "If they had stayed with us, they would not have died or been killed," so that Allah may make it a cause of regret in their hearts. It is Allah that gives life and causes death. And Allah is All-Seer of what you do.

(16) And that He might test the hypocrites, it was said to them: "Come, fight in the Way of Allah or (at least) defend yourselves." They said: "Had we known that fighting will take place, we would certainly have followed you." They were that day, nearer to disbelief than to Faith, saying with their mouths what was not in their hearts. And Allah has full knowledge of what they conceal.

(17) They (hypocrites) are those of whom Allah knows what is in their hearts; so turn aside from them (do not punish them) but admonish them, and speak to them an effective word (i.e. to believe in Allah, worship Him, obey Him, and be afraid of Him) to reach their innerselves.

(18) O you who believe! Stand out firmly for justice, as witnesses to Allah, even though it be against yourselves, or your parents, or your kin, be he rich or poor, Allah is a Better Protector to both (than you). So follow not the lusts (of your hearts), lest you avoid justice; and if you distort your witness or refuse to give it, verily, Allah is Ever Well-Acquainted with what you do.

(19) Because of their breaking the covenant, and of their rejecting the Ayat (proofs, evidence, verses, lessons, signs, revelations, etc.) of Allah, and of their killing the Prophets unjustly, and of their saying: "Our hearts are wrapped (with coverings, i.e. we do not understand what the Messengers say)" - nay, Allah has set a seal upon their hearts because of their disbelief, so they believe not but a little.

(20) So, because of their breach of their covenant, We cursed them and made their hearts grow hard. They change the words from their (right) places and have abandoned a good part of the Message that was sent to them. And you will not cease to discover deceit in them, except a few of them. But forgive them and overlook (their misdeeds). Verily, Allah loves Al-Muhsinun (good-doers - See V.2:112).