The one who regrets his or her mistake, right after do good deeds, and will try not to make the same mistake twice
And [recall] when Moses said to his people, “O my people, indeed you have wronged yourselves by your taking of the calf [for worship]. So repent to your Creator and kill yourselves. That is best for [all of] you in the sight of your Creator.” Then He accepted your repentance; indeed, He is the Accepting of repentance, the Merciful. [2:54]
Indeed, those who conceal what We sent down of clear proofs and guidance after We made it clear for the people in the Scripture – those are cursed by Allah and cursed by those who curse. [2:159]