Quite true. As we are not just guilty of sin on occasion, we are sinful by nature, sometimes we are not even aware of a sinful course until it is brought to our attention. That only magnifies the value of the ransom sacrifice and also our need for it. Once we have dedicated ourselves on the basis of the ransom, Jehovah can apply its benefit to the sins we are not aware of yet because it covers our sinful condition. It is important to pray for forgiveness even if we are not conscious of specific sins because Jehovah knows we would be repentant once we become aware of them. (Heb.9:7)
When we discussed Romans 2:4 in Study 34 last year, we saw that the kindly quality of God is trying to lead individuals to repentance. The illustration of a shepherd who locates a lost sheep, perhaps injured and entangled in a dangerous position, is fitting here. He tries to reassure the sheep that safety is near, that the possibly frightened injured animal can trust the shepherd. He gently coaxes the sheep along, freeing it from entanglement, may have to carry it to safety, then apply whatever remedy to soothe its injuries, start the healing process, and then care for it until fully recovered. So we can glean from this that, while repentance begins as a process, it can reach a completed condition.
If a repentant sinner still feels that they are unworthy of Jehovahs restored affection even though though they have turned away from a sinful course, this is understandable, but could be a good thing, a sign of a humility rather than a lack of faith. But Jehovah cares deeply that he should be restored fully in a spritual way, so he should meditate on David's words in Ps.51, particularly v10, and request Jehovah to create in him "a pure heart". That would include a proper estimation of his restored relationship with our kindly God, Jehovah, who is leading him to full and complete repentance. Jehovah will answer that prayer. 😊