Dear Rabbi "On Yom Kippur, G-d mercifully erases all the sins we have committed "before G-d"—but not the sins we may have committed against our fellow man." There is this fellow Jewish child, whom I had wronged during my childhood, I dont have the opportunity to contact or communicate with him (ever again). I sincerely apologize for my actions and am deeply ashamed of my actions. I aspire to perform Teshuvah on his behalf. I will cease any wrongdoing towards my fellow Yidden and make a confession to Hashem, perform viduy, and offer tzedakhah. I have read the following on Dinonline : As a side point, the Vilna Gaon says that a person who wronged someone else, and can’t find the person, etc., should do whatever is in his ability to do to try to correct what was done, and when Hashem sees that the person tried the best they can, He will arrange it that the other half of the sin will get corrected also. Therefore, the person should do whatever humanly possible for them to do to get forgiveness, including davening, that the person should be mochel you. After that we hope that Hashem, in His unending kindness will arrange things so that the other person will be mochel. Can I improve? Will Hashem arrange for the sin to be corrected?

Shalom, The idea that the Holy One, blessed be He, sees a person's sincere efforts in repentance and, in His mercy, arranges that the matter should be rectified, does indeed appear in several sources. I do not know whether the Vilna Gaon actually wrote these words explicitly anywhere. I did see a story (brought in the name of the book Mekarvan LaTorah) that Rabbi Zalman of Volozhin, a student of the Vilna Gaon and the brother of Rabbi Chaim of Volozhin, once felt great anguish because he had insulted another Jew and was unable to find that person in order to ask for his forgiveness. The Vilna Gaon comforted and reassured his student with the words of the Chovot HaLevavot (Sha'ar HaTeshuvah, chapter 10), who explains that when the Holy One, blessed be He, sees a person's sincere desire to repent, He arranges matters so that the person who was harmed will forgive the one who harmed him, or that the appropriate restitution will be made. This principle was also written by Maran Rabbi Avraham Yitzchak HaKohen Kook, zt"l (who was described by his student Rabbi Yitzchak Hutner as "a man of the Vilna Gaon," meaning that he was deeply attached to the teachings of the Vilna Gaon) in several places in Orot HaTeshuvah (10:6, 7:6, 14:4, 17:2). In summary: Strengthen yourself Chazak veematz! With God's help, your prayers and repentance will be accepted favorably, and everything will ultimately be rectified. Further explanation: As mentioned, the Chovot HaLevavot (ibid.) writes that when a person returns in genuine and complete repentance, God causes even the consequences of the sin to be arranged and rectified: "If the matter concerns forbidden relationships, as in the case of one who had a child from a forbidden relationship, the Creator will remove his offspring. If it concerns fraud or theft in monetary matters, God will provide him with money, and he will repay his fellow, appease him, and receive his forgiveness. If he harmed his fellow physically or damaged his reputation, the Creator, blessed be He, will place in that person's heart a desire and love until he forgives him for what he had suffered because of him, as it says: 'When a man's ways please the Lord, He makes even his enemies be at peace with him' (Proverbs 16:7). If the person who was wronged has distanced himself, God will arrange for them to meet, until the one who caused the harm humbles himself before him and receives forgiveness. If he does not know the identity of those he harmed or the amount of money he stole, God will enable him to spend his money on public benefits, such as building bridges, digging wells, and creating other things that benefit the community, until the benefit reaches both those he harmed and those he did not harm." Similarly, Rabbi Avraham Yitzchak HaKohen Kook writes in Orot HaTeshuvah (10:6) that through repentance and a strong commitment not to return to the sin, God will increase a person's opportunities to practically repair his wrongdoings. He writes: "However, regarding sins between man and his fellow, the soul cannot reach perfection until they are practically repaired. Sometimes obstacles and impediments arise that cannot be overcome, and as long as they have not been repaired, they prevent the light of knowledge from illuminating the soul, and consequently hinder the recognition of universal justice and the desire for it to emerge from concealment. Nevertheless, through a strong resolve to at least be careful in the future not to sin against others, and to strive to repair the past according to the degree that repentance is expressed in action, the spiritual light will continue to shine upon the soul until the strength of the spirit itself creates new ways to complete the practical repentance, so that the spiritual light may rest upon the soul that longs for it, in its full measure and goodness." In Orot HaTeshuvah (7:6), Rabbi Kook added further encouragement: sins are nullified when they are outweighed by the majority of one's merits and a person is judged according to his overall state. He writes: "If a person finds within himself sins between man and his fellow, and his ability to repair them is weak, nevertheless he should never despair of the great remedy of repentance. For the sins between man and God for which he repented are forgiven. Therefore, it can be considered that the remaining parts that he has not yet repaired are nullified by the majority, since many parts of his sins have already been forgiven through his repentance. Nevertheless, he should not cease being extremely careful not to stumble in any sin between man and his fellow, and he should repair as much as he can from the past with wisdom and great strength of spirit." In the book Minchat Asher on Vayikra (52:5), Rabbi Asher Weiss discusses the view attributed to Rabbi Yisrael Salanter that someone who spoke lashon hara (slander) about another person should not ask that person for forgiveness if doing so would cause him additional pain, but nevertheless the sin of lashon hara would not be atoned for. The Minchat Asher disagrees and writes that the atonement of the speaker is not dependent on the person about whom he spoke, but rather on God. "For is he in the place of God to grant atonement?" Rather, requesting forgiveness is part of the process of repentance: instead of causing pain and harm, the person now seeks to appease and benefit the one he hurt. It is logical that if reconciliation would cause additional suffering, there is no obligation whatsoever to seek forgiveness, and therefore the lack of requesting forgiveness does not prevent his atonement. (See there.) In an oral lecture (available on Kol Halashon, "Yom Kippur – How Are Sins Between Man and His Fellow Atoned For?", section 7, Tishrei 5780), Rabbi Asher Weiss explained further that in any case where a person truly wants to perform complete repentance and, from his perspective, would ask for forgiveness, but circumstances prevent him from doing so, he can still receive atonement without asking for forgiveness. He gave several examples: One example is if a person wronged someone who has since passed away and therefore cannot be asked for forgiveness, but he has sincerely repented and simply has no ability to request forgiveness, his sin can be completely atoned for. He elaborated on this extensively. Rabbi Asher Weiss noted that several later authorities disagree with his approach, but he rejected their arguments.