What is the ruling on one who repents and fears that he will not be forgiven?

Question:
I am a person who has committed many sins, among the sins and transgressions. But praise be to Allah, Lord of the worlds, who has granted me guidance. My life has changed, but I feel in my heart that Allah will not forgive me for the sins I committed before. What do you advise me to do?
On this blessed occasion, I ask you by Allah, there is no deity but He, to make a supplication for me and for everyone like me in this blessed, good place, asking for forgiveness and acceptance, so that perhaps Allah (Glorified and Exalted is He) may overlook us and reward you for us.

Answer:
I ask Allah to accept your repentance, and to rectify your heart, your deeds, and the affairs of all Muslims. I ask Allah to rectify our hearts and our deeds all together, and to grant us sincere repentance, and to guide us to His straight path, and to protect us from the evils of our own selves and from the badness of our deeds.
We advise you to have good opinion of Allah. You must have good opinion of Allah. Beware of whispers and bad opinion of Allah. As long as you have repented from your bad deeds, praise Allah and ask Him to accept from you. Beware of returning to evil and sins, and beware of returning to the company of the wicked. Do not keep company with the wicked, and keep company with the righteous. Have good opinion of your Lord. The Prophet (peace and blessings be upon him) said: : I am as My slave thinks of Me, and I am with him when he calls upon Me. So whoever has a good opinion of Allah gains the greatest of gains.
So you must have a good opinion of Allah, and call upon Him to keep you firm upon the truth, to guide you to His straight path, and to make your ending good. Beware of the whispers of Satan and bad opinion of Allah . And he (peace and blessings be upon him) said: . So Satan is eager to mislead the children of Adam and corrupt their deeds. And when they repent, he whispers to them that your repentance is not accepted, that your past sins are great, and that you will not be safe from their evil. This is all from his deception, and all of it is from his injustice and aggression. So you must beware of the whispers of Satan, and remember His saying: [al-Nur:31], and He says (Glorified is He): [al-Tahrim:8], and hope from Allah is obligatory.
And the Prophet (peace and blessings be upon him) said: , and he (peace and blessings be upon him) said: . So whoever repents with a sincere repentance, with regret for the past, and abandoning it, and a sincere resolve not to return to it; Allah will repent toward him and pardon him . And if the repentance is from the right of a created being, then a fourth matter is necessary, which is: returning the right to its owner, such as theft and usurpation and the like. It is necessary to return the right to its owner, or to seek his pardon and permission, until the repentance is complete.
So the conditions are three. Repentance has three conditions:
Regret for the past.
And abandoning the sin and leaving it out of fear of Allah and exalting Him.
And the third matter: a sincere resolve not to return to it.
And there is a fourth matter if the sin relates to a created being: that it is necessary to seek his pardon, or return his right to him, such as the killer, the thief, and the usurper. It is necessary to return the right to its owner, or seek their pardon, otherwise the repentance will not be complete.