Is this ok to use her fb page in a review if she has no other web site ?

The review would not be accepted by TER.

I assume that she has a fb account in her provider name,  not her RL account.  
Rather unusual but in that case,  who cares.  

Begs the question (and padantic putzes please don't) how you first discovered her.

Even if she tells you do so - it is unwise and don’t do it!

Ummm ... how is that "outing" her?  Assuming her Facebook handle is her provider identity (that must be how the OP got it) she is already public as providing with that handle.  
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If she's so security-oblivious that she gave a client her real-life civvie handle, then I agree not to out her; but then she has worse problems that I'd not want to be part of.

Not to be pedantic...

...but it's spelled "p e d a n t i c"...  

Unfortunately we all have to assume a lot since the OP provided zero context. I’m assuming that he has her real life FB account because he didn’t specify it as a FB account with her working name.

It would have helped if he told us how he got her Facebook account. Does he know her from school or work? Did he randomly DM the girl and end up working an arrangement out with her? Did she show him some pics from her FB account on her phone during the session? Did he find her FB page doing an image search? Did he come across her Facebook page via stalking type activity? If the answer to any of those questions is yes, than the account can’t be used in a review.

The only scenario where he could use her FB account would be  if it was a separate FB account created by the provider for the purpose of escorting.  The likelihood that this is the OP’s situation is extremely low. So low that I don’t see the TER admins approving a review with a FB link under any circumstances.

I use to have a professional account on Facebook, I don't use it a lot coz they're very puritans and remove the page easy. I lost many of them, this can be the problem, If Facebook remove the site banning it, you will lost the info for the review. Of course never publish personal facebook or any kind of information.