I think she and her handlers at CNN and MSNBC had best tread carefully. All the money in the world won't be useful to her behind bars if Trump decides that is the angle to address this pariah.
Thoughts?
I'm not an attorney but I'll try my hand at a legal analysis.
From what I've read thus far, Trump required all of his "trysts" to sign a non-disclosure agreement regarding their activities (Shades of Grey?). She was paid money in exchange for her silence. Supposedly she wants to give the money back presumably thinking it will release her from the gag order she originally agreed to so she can then presumably dish on what occurred.
Violating a written contract in this manner is generally a civil matter not a crime.
Extortion is a form of theft that occurs when an offender obtains money, property, or services from another person through coercion. To constitute coercion, the necessary act can be the threat of violence, destruction of property, or improper government action. Inaction of the testimony or the withholding of testimony in a legal action are also acts that constitute coercion
Blackmail, in contrast to extortion, is when the offender threatens to reveal information about a victim or his family members that is potentially embarrassing, socially damaging, or incriminating unless a demand for money, property, or services is met. Even if the information is true or actually incriminating, you can still be charged with blackmail if you threaten to reveal it unless the victim meets your demand.
So what is Daniels demanding from Trump in exchange for her silence / continued silence in order to be charged with blackmail because it doesn't appear that the definition of extortion fits this scenario.
Also my understanding is that we all have certain rights that we can not sign away or agree to. If the reports that Daniels was or has been threatened with physical harm are true, then signing the NDA will not protect any of the parties from criminal prosecution if it were ever to come to that. In other words, you can't use a contract to hide behind in order to commit acts that are not lawful.