Admission of wrongdoing is first step towards true repentance.

No one who lives in him keeps on sinning. No one who continues to sin has either seen him or known him.

-I John 3:6, NIV

Does the cheater willingly admit the cheating was sin? Or is the cheating minimized as something less than wrong? Does the cheater try and “justify” the cheating and lying as “not so bad?”

I hold little hope for a sinner who is still in love with the sin.

Y0u have to admit there is a problem before that problem can be fixed. A cheater unwilling to admit their lying and cheating is wrong is a person in denial of the problems.

They cannot turn from their sin if they do not think it is sin.

This is the first step towards repentance–that is admitting the sin exists. A cheater pouring all their energy in avoiding such an admission is a cheater who is running from God and repentance.

God allows us to run from Him, though.

As God leads us, we are charged to speak truth with love. We do not agree with the lies about sin as that only serves the destruction of the person caught in the sin (plus, it harms the victims of said sin).

That said, it is the Holy Spirit whose job is to convict of sin. NOT us!