The word(s) "hearts" appears 136 time(s) in 127 verse(s) in Quran in Muhammad Habib Shakir translation.

(101) Those of the dwellers of the desert who were left behind will say to you: Our property and our families kept us busy, so ask forgiveness for us. They say with their tongues what is not in their hearts. Say: Then who can control anything for you from Allah if He intends to do you harm or if He intends to do you good; nay, Allah is Aware of what you do:

(102) Nay! you rather thought that the Apostle and the believers would not return to their families ever, and that was made fairseeming to your hearts and you thought an evil thought and you were a people doomed to perish.

(103) Certainly Allah was well pleased with the believers when they swore allegiance to you under the tree, and He knew what was in their hearts, so He sent down tranquillity on them and rewarded them with a near victory,

(104) When those who disbelieved harbored in their hearts (feelings of) disdain, the disdain of (the days of) ignorance, but Allah sent down His tranquillity on His Apostle and on the believers, and made them keep the word of guarding (against evil), and they were entitled to it and worthy of it; and Allah is Cognizant of all things.

(105) Surely those who lower their voices before Allah's Apostle are they whose hearts Allah has proved for guarding (against evil); they shall have forgiveness and a great reward.

(106) And know that among you is Allah's Apostle; should he obey you in many a matter, you would surely fall into distress, but Allah has endeared the faith to you and has made it seemly in your hearts, and He has made hateful to you unbelief and transgression and disobedience; these it is that are the followers of a right way.

(107) The dwellers of the desert say: We believe. Say: You do not believe but say, We submit; and faith has not yet entered into your hearts; and if you obey Allah and His Apostle, He will not diminish aught of your deeds; surely Allah is Forgiving, Merciful.

(108) He causes the night to enter in upon the day, and causes the day to enter in upon the night, and He is Cognizant of what is in the hearts.

(109) Has not the time yet come for those who believe that their hearts should be humble for the remembrance of Allah and what has come down of the truth? And that they should not be like those who were given the Book before, but the time became prolonged to them, so their hearts hardened, and most of them are transgressors.

(110) Then We made Our apostles to follow in their footsteps, and We sent Isa son of Marium afterwards, and We gave him the Injeel, and We put in the hearts of those who followed him kindness and mercy; and (as for) monkery, they innovated it-- We did not prescribe it to them-- only to seek Allah's pleasure, but they did not observe it with its due observance; so We gave to those of them who believed their reward, and most of them are transgressors.