The word(s) "heart" appears 213 time(s) in 195 verse(s) in Quran in Abdullah Yusuf Ali translation.

(11) O ye who believe! Enter into Islam whole-heartedly; and follow not the footsteps of the evil one; for he is to you an avowed enemy.

(12) Allah will not call you to account for thoughtlessness in your oaths, but for the intention in your hearts; and He is Oft-forgiving, Most Forbearing.

(13) There is no blame on you if ye make an offer of betrothal or hold it in your hearts. Allah knows that ye cherish them in your hearts: But do not make a secret contract with them except in terms Honourable, nor resolve on the tie of marriage till the term prescribed is fulfilled. And know that Allah Knoweth what is in your hearts, and take heed of Him; and know that Allah is Oft-forgiving, Most Forbearing.

(14) When Abraham said: "Show me, Lord, how You will raise the dead, " He replied: "Have you no faith?" He said "Yes, but just to reassure my heart." Allah said, "Take four birds, draw them to you, and cut their bodies to pieces. Scatter them over the mountain-tops, then call them back. They will come swiftly to you. Know that Allah is Mighty, Wise."

(15) If ye are on a journey, and cannot find a scribe, a pledge with possession (may serve the purpose). And if one of you deposits a thing on trust with another, Let the trustee (Faithfully) discharge His trust, and let him fear his Lord. Conceal not evidence; for whoever conceals it,- His heart is tainted with sin. And Allah Knoweth all that ye do.

(16) He it is Who has sent down to thee the Book: In it are verses basic or fundamental (of established meaning); they are the foundation of the Book: others are allegorical. But those in whose hearts is perversity follow the part thereof that is allegorical, seeking discord, and searching for its hidden meanings, but no one knows its hidden meanings except Allah. And those who are firmly grounded in knowledge say: "We believe in the Book; the whole of it is from our Lord:" and none will grasp the Message except men of understanding.

(17) "Our Lord!" (they say), "Let not our hearts deviate now after Thou hast guided us, but grant us mercy from Thine own Presence; for Thou art the Grantor of bounties without measure.

(18) Say: "Whether ye hide what is in your hearts or reveal it, Allah knows it all: He knows what is in the heavens, and what is on earth. And Allah has power over all things.

(19) And hold fast, all together, by the rope which Allah (stretches out for you), and be not divided among yourselves; and remember with gratitude Allah's favour on you; for ye were enemies and He joined your hearts in love, so that by His Grace, ye became brethren; and ye were on the brink of the pit of Fire, and He saved you from it. Thus doth Allah make His Signs clear to you: That ye may be guided.

(20) O ye who believe! Take not into your intimacy those outside your ranks: They will not fail to corrupt you. They only desire your ruin: Rank hatred has already appeared from their mouths: What their hearts conceal is far worse. We have made plain to you the Signs, if ye have wisdom.