There's no proof, so the claim is just as plausible as the original accusation against Trump.
It doesn't help anyone to repeat something like this, without corroboration of some sort.
Not only is there no proof, the proof if it exists is likely protected by attorney client privilege. It would be hard to pierce that veil. She would have to come out and confess, or others who were given the offers, if such offers were given, were to release their communications. But if this is true and documents do exist. I would bet that it was written in such a way that the money was not paid to make an accusation, but paid out by a third party to the accuser as an advance against a future verdict or settlement won in a civil lawsuit.