Is one absolved of responsibility and is repentance accepted when restituting grievances merely by the wronged person saying, "I have forgiven you," even if their heart is not completely content?

If a person voluntarily forgives his right and waives what is due to him from another, while being competent to do so, then the debtor's liability is cleared. So, if he says to you: "I forgive you," he has waived his right, and your liability is cleared. What he conceals in his heart does not affect the waiving of his right, which was done by his free choice.