How can a man prove his innocence against a false accusation of physical harassment by a girl, especially given that society tends to believe the girl, and would he be judged or dismissed from his job based on this accusation?

The basic principle is the acquittal of people's liabilities, and the accused is innocent until proven guilty by evidence. As long as the girl does not provide evidence for her claim, no judgment can be made against the man. Rather, the man has the right to demand that the girl be subjected to discretionary punishment for accusing him without evidence.