Which heart deserves Allah's grace?

إِلَّا مَنْ أَتَى اللَّهَ بِقَلْبٍ سَلِيمٍ

“But only he (will prosper) that brings to Allah Ta’ala a sound heart”. (26:89)

How can a heart become illumined when it has been penetrated by worldly wealth, worldly reputation, offspring, property, idle thoughts and false hopes? When the darkness of the phantoms is dispelled from the heart, Noor will then settle in the heart.

The heart which night and day is fettered in the chains of nafsaani desires, thinking only of food, garments and wives, cannot advance towards Allah Ta'ala because its feet are tied with chains.
The heart which has not been cleansed of the impurities of neglect (ghaflat) and perpetually dwells in negligence, having forgotten the akhirat, cannot enter into the lofty Divine Presence. How can such a heart be granted acceptance in such a pure Court?
Just as an impure (napaak) person is not permitted entry into a Musjid, so too is a heart which has not been purified of the impurities of ghaflat denied entry into the Divine Presence. Such a heart is not granted Divine Acceptance.
The heart which is engrossed in despicable acts, futility and baseless hopes cannot entertain the desire to comprehend the mysteries and subtleties of Allah Ta'ala. When it has repented of its futility, then only will it be endowed with the ability to understand Divine Mysteries.
-Ikmalus Shiyam, commentary on the Hikam