Is it necessary to be certain after sincere repentance that God has forgiven and erased the sin?

If repentance is sincere and fulfills its conditions, then Allah accepts it and erases the effect of the sin thereby. This is the view of the majority of scholars. The servant should be concerned with achieving sincere repentance, for the truthful repentant person remains fearful that his repentance may not be accepted, and accusing one's own repentance is a sign of its acceptance.

Among the signs of accepted repentance is that the repentant person, after repentance, is better than he was before it; that fear remains his constant companion, so he does not feel safe from Allah's plan for even a blink of an eye; and that his heart is rent with remorse and fear. This rending of the heart with sorrow and fear is the essence of repentance.