Scammers are very creative, so you have to pay attention to (but not limited) the red flags:
- Offer is incredible higher than usual (not 100% red flag - maybe the buyer really wants your website, but generally speaking it's a red flag).
- He propose to transfer the domain name & other assets first, and to send the money later (.).
- He propose to use PayPal, without F&F, and do not accept an escrow service.
- ...have a bad reputation, or a faked identity.
- ...trying to speed-up things and offer you money through unknown/shady methods (eg: pose as a very busy entrepreneur who wants to pay you through crypto, on known scam crypto sites).
There are other red flags, but the ones mentioned above are most common. As a general rule, don't provide the auth code for the domain transfer before you get the money (or the money have been deposited in a safe place, like escrow). Don't transfer valuable social media accounts, or any other assets.
Scammers are everywhere: on FB, on Flippa, and so on. The seller must do his due diligence.
Cheers!
R