for the car. With Cash there is no record and he could claim the car was stolen or you never paid for it. It’s not likely he would do that because most ppl are honest but if you want to be safe do the following:

If he wants cash, go with him to your bank. Get a cashiers check made out to him with the vehicle vin in the memo. He can immediately right then and there cash the check and have his cash and you have a record that you paid for the car. Bit of a hassle but it’s the best way to buy a car without getting scammed imo.