Agreement to Drop Charges

I’m hoping for some good advice.

My wife’s brother has been charged with rape and kidnapping his apparent former girlfriend. We live in the US and I have no idea about the merits of the case one way or the other. Seems like it’s her word against his and I don’t know who to believe.

However, the alleged victim offered to not continue to press charges if she’s payed a sum of money. Is this something that can be legally arranged in the Philippines and is it enforceable? How can we be assured she doesn’t change her mind after she is paid or ask for more money? Can the prosecutor still press charges even without her testimony? We just want to make sure what we’re being asked to do is both legal and not a scam. Thanks for any insight you can provide. Salamat.

She should issue an affidavit of desistance at the prosecutor's office so it can be used against her if she tries to re-fil

Thank you for the advice. Follow-up... can the prosecutor still press charges on behalf of the state? And it sounds like the Affidavit isn’t a sure thing If she can try to refile charges? I appreciate your help.