Praise be to Allah.
If a person commits major and minor sins, it is still possible for him to be admitted to Paradise without being brought to account, if he repents and turns back to Allah. Allah, may He be exalted, turns the bad deeds of the one who repents to good deeds, even if he committed shirk, murder and zina, as He says (interpretation of the meaning):
“And those who do not invoke with Allah another deity or kill the soul which Allah has forbidden [to be killed], except by right, and do not commit unlawful sexual intercourse. And whoever should do that will meet a penalty.
Multiplied for him is the punishment on the Day of Resurrection, and he will abide therein humiliated -
Except for those who repent, believe and do righteous work. For them Allah will replace their evil deeds with good. And ever is Allah Forgiving and Merciful”
[al-Furqaan 25:68-70].
All that the one who has committed sins has to do is repent and ask Allah, may He be exalted, to accept his repentance and admit him to Paradise without bringing him to account.
As for the one who meets Allah with major sins from which he has not repented, then the matter is subject to the will of Allah: if He wills He will punish him, and if He wills He will forgive him, because Allah, may He be exalted, says (interpretation of the meaning):
“Indeed, Allah does not forgive association with Him, but He forgives what is less than that for whom He wills”
[an-Nisa’ 4:48].
Turning bad deeds, sins, wrong deeds, evil deeds into good deeds, repentance from zina and adultery, punishments for major sins, big sins and evil deeds, repentance