Being afraid that your repentence
Will Not Be Accepted

Question :

A person committed some act of disobedience and afterwards repented to Allâh; however, he feels deep inside himself that Allah will not forgive him. So what is your advice for him?

Answer:

This is among the proofs of the severity of your fear of Allah Almighty and your reverence for His prohibitions, if Allah wills, you are doing what is right. Nevertheless, you should try to allay this fear, a fear that has no basis for it because it is from the Shaytan. He wants you to feel constricted and he wants you to be miserable. Know him by what he is an unmitigated enemy. He hates to see you loving and doing what is good, so disobey him and abstain from what he orders you to do.

Seek peace in your Lord and know that repentance is sufficient. Even if a sin is greater than all other sins, repentance to Allah Almighty is above it. There is no greater sin than Shirk, but even if a man who associates partners with Allah repents and turns back to Allâh, He will forgive him. So it is required of you to repent from what you have done and after repentance to cease these other matters. It is not required of you to listen to the whispering or to follow the enemy of Allâh by this fear which has harmed you. But know that thanks to Allah Almighty you have succeeded a great success by repenting sincerely, as Allâh Almighty says:
"And verily I am indeed forgiving to him who repents, believes and does righteous deeds, then follow the right way."

There is another verse of even greater purport, for it states that a person who, after sinning, repents, has faith, and does good deeds, Allah Almighty will transform his sins into good deeds, which means that He will put a good deed in the place of every bad one:
"And those who invoke not any other ilah (god) along with Allah, nor kill such life as Allah has forbidden, except for just cause, nor commit illegal sexual intercourse and whoever does this shall receive the punishment. The torment will be doubled to him on the day of Resurrection, and he will abide therein in disgrace; except those who repent and believe, and do righteous deeds, for those, Allah will change their sins into good deeds, and Allah is Oft- Forgiving, Most Merciful".

Allah Almighty informed us here that he transforms their bad deeds into good ones because of their sincere repentance, their faith, and their good deeds. So you, by pondering over your sins which are an offence to Him, and by your repentance from that and your following that with what you do of righteous deeds. and faith and conviction, hoping in the rewards with Allâh Almighty, then you are exchanging your evil deeds for good.

This is the same with all of the evil which the servant repents from and follows up with faith and righteous deeds, Allâh exchanges them for good, out of His grace and beneficence, glorious is He the Almighty.

Source:
Ibn Baz
Fatawa Islamiyah, Vol. 7 Pages 243-244-245