I'm not an attorney, but I don't think that's true. The defining element of the fraud is deception. That can be verbal or written.
It is, of course, much more difficult to prove a fraud without written evidence.
I do know here in Florida there has been some high-visibility prosecutions of people for defrauding old folks. The contracts they signed were entirely legal, but their signature was obtained by false verbal inducements.
I used to be a commercial real estate agent. Back then it was all about getting your contract (to find a lessee) in writing or you would get stiffed for the commission. Sure, you coult try to fight it, but it is basically “he said, she said” without a contract.
And with this sort of thing, it is LITERALLY he said, she said. No written contract, no case.
This whole thing is absurd on the face of it. It’s why I guessed it was a democrat proposing it. It means that it would be technically illegal for a guy to say he loved a girl just to get her to “put out” (Not that it is not sleazy and immoral). It’s nuts to get the law involved in such things.