As Mike Brewer advises, “Nelsons.” (Nelson Eddies = readies.) Do the deal, then meet the buyer in a bank during banking hours where he pays you cash and you immediately bank the cash. That is the only 100 per cent safe way of taking payment and releasing the car to the buyer the same day. A test drive is illegal unless the buyer is insured. He might be insured to drive your car third party on his own insurance. He might not. You need to see his certificate.

Better to use www.sure-sell.info that saves the cost of advertising, taking phone calls from conmen, waiting for buyers who don't show up, illegal test drives, intimidation and problems with the method of payment.