Safest way to take payment for car from out of state buyer

In person. Don't it is all a scam. Unless they are in person, the vehicle is in your presence, and you have the title, there is not a single safe way to buy a car out of state.

Ask your banker. Cash or a cashiers check drawn on your bank and verified by your bank should be OK.

There are so many swindles from out-of-state car buyers I would recommend only taking cash in person. A big scam is for a buyer to overpay by check, then asking you to send the extra amount to a "shipper" who will then come get the car. It's only later you learn the check was bogus, and the extra amount you sent off to the shipper was the scammer's payoff.