Is it obligatory to go to a female relative to repent to her and ask for forgiveness after having harassed her, or should one continue in religious observance and perpetual repentance, and is repentance accepted for a sin that pertains to the rights of human beings?

We congratulate you on your repentance, remorse, and memorization of the Book of Allah. We advise you to remain steadfast in righteousness, beneficial knowledge, and good deeds. You are not required to seek forgiveness from the girl or her family, as that might lead to a greater harm. It is sufficient for you to supplicate for them and seek forgiveness, and to have good faith in Allah, who accepts repentance and pardons sins. Beware of despairing and losing hope in Allah's mercy, for these are major sins and whispers from Satan. Increase in good deeds and invest your time in what benefits you in this world and the Hereafter.