Look at the reviewer's own history on the platform. A profile with a single review, posted within 24 hours of several others for the same agent, is a pattern worth noticing, while a reviewer with a broader history posting one detailed, specific account reads very differently.
Ask the agent directly for the client's name and permission to call them, or for the closing date the review refers to. A real client will not mind confirming details a recruited reviewer was never given in the first place.
Joel Dyck would rather lose a review than manufacture one, and he will connect you with a past client directly if you want to hear it firsthand rather than read it. Get your hand-reviewed valuation from Joel Dyck.