Harassment by girl for marriage

If a person want himself to be blackmailed by frivolous and false chriminal charges by another person than nothing can be done, but if he really want to take action against such blackmailer, best course if first to record stament of the blackmailer and file criminal complaint such person under section 506 IPC for criminal intimidation with help of the recorded statement where the admission of indulging in relationship by free consent and no demand made at that time of legalising the relationship with marriage. The demand of marriage was after thought and after many days/months just in order to make money etc from the person so blackmailed.

You must file a pre emptive complaint against the said girl at the local police station. The police shall obviously not take any action. But then you may be able to avail the benefit of this at the time of applying for anticipatory bail.