Is it incumbent upon one who desires sincere repentance (tawbah nasuh) to open a new chapter in their life and acts of worship and forget the past, or should they return to their previous state, which was one of piety and righteousness, before they were afflicted by sins?

The sinner must initiate sincere repentance, for repentance erases previous sins, no matter how great they were. Allah Almighty says: "And it is He who accepts repentance from His servants and pardons sins." The Prophet, peace and blessings be upon him, said: "The one who repents from sin is like one who has no sin." There is no human being infallible from sins, for all humans are sinners, and the best of sinners are those who repent. So, let this person initiate sincere repentance, and let him know that Allah's forgiveness is greater than any sin, and let him open a new page in his life, resolving therein to obey Allah and to be steadfast upon His law.