Your deed of sale has to be notarized. The seller is responsible for providing a notarized bill of sale. I have had foreigners sell me a vehicle with an 'unnotarized' bill of sale that they drew up and it gave me a world of problems. I won't do that again.
When I sold my truck I went to a lawyer with my registration and the purchasers details and said: Please draw up a bill of sale and notarize it for me. Then I took the bill of sale to the buyer and he gave me the cash. Simple as 1 2 3 when you do it right.