The word(s) "hearts" appears 159 time(s) in 147 verse(s) in Quran in Abdullah Yusuf Ali translation.

(111) (Allah) knows of (the tricks) that deceive with the eyes, and all that the hearts (of men) conceal.

(112) And there are (other) advantages in them for you (besides); that ye may through them attain to any need (there may be) in your hearts; and on them and on ships ye are carried.

(113) They say: "Our hearts are under veils, (concealed) from that to which thou dost invite us, and in our ears in a deafness, and between us and thee is a screen: so do thou (what thou wilt); for us, we shall do (what we will!)"

(114) What! Do they say, "He has forged a falsehood against Allah"? But if Allah willed, He could seal up thy heart. And Allah blots out Vanity, and proves the Truth by His Words. For He knows well the secrets of all hearts.

(115) And among them are men who listen to thee, but in the end, when they go out from thee, they say to those who have received Knowledge, "What is it he said just then?" Such are men whose hearts Allah has sealed, and who follow their own lusts.

(116) Those who believe say, "Why is not a sura sent down (for us)?" But when a sura of basic or categorical meaning is revealed, and fighting is mentioned therein, thou wilt see those in whose hearts is a disease looking at thee with a look of one in swoon at the approach of death. But more fitting for them-

(117) Do they not then earnestly seek to understand the Qur'an, or are their hearts locked up by them?

(118) Or do those in whose hearts is a disease, think that Allah will not bring to light all their rancour?

(119) It is He Who sent down tranquillity into the hearts of the Believers, that they may add faith to their faith;- for to Allah belong the Forces of the heavens and the earth; and Allah is Full of Knowledge and Wisdom;-

(120) The desert Arabs who lagged behind will say to thee: "We were engaged in (looking after) our flocks and herds, and our families: do thou then ask forgiveness for us." They say with their tongues what is not in their hearts. Say: "Who then has any power at all (to intervene) on your behalf with Allah, if His Will is to give you some loss or to give you some profit? But Allah is well acquainted with all that ye do.