If the heart is deceitful above all things as we are so informed in the verse below, then how can it un-deceitfulize (sorry, my word) itself? It can't, and so, those who have a good heart, have it, only because they have been given it. So, the question then becomes, can someone with a heart completely deceitful give to himself true faith without first having received a new heart?
[Jer 17:9-10 KJV] 9 The heart [is] deceitful above all [things], and desperately wicked: who can know it?