Classic Plus Auto

I had listed my 1951 Chevy on Craigslist for sale asking $5000. Mr Haugrud responded. He asked about condition. I sent him pictures of the interior and some of the outside of the car. He told me he was coming from Detroit Lakes. I told him that I didn't want him to make the trip if it wasn't what he was expecting. He told me he was bringing a trailer and was intending to buy. I told him I wanted someone to have the car that would drive it. He said he was planning on driving it. He arrived exactly at 4:00pm as agreed.
He looked at the car and told me that there was a lot of rust. He pointed out some places on the door. I looked under the car and did see some rust but I do not know what I was looking at. I do not have much knowledge of automobiles. He told me he had a lift and knew how to weld. 
He asked if I would take $2500. I asked him for $3000. He repeated there was a lot of rust. I accepted his offer. I helped him load the car onto his trailer. I asked him for pictures when he was done with the car. He gave me the money in cash and I completed the title for a private sale. For a private sale the state requires the seller to notify them of the sale within 10 days. On April 26, I started to notify the state with the information I received from Mr Haugrud. I noticed discrepancy between what he told me and what he had written down. The first thing was he had a Lake Park address not a Detroit Lakes address. 
They wanted his Driver License number which he had not given me. I contacted him for his driver license number and he told me he was a licensed dealer in MN. He wanted me to give the state his dealer license number. I told him that a sale to a licensed dealer did not require me to tell the state. He agreed. He said he did not tell me he was a dealer because some people do not like dealers. I told him I would have preferred honesty. He said they had cleaned the car up. Got it started and drove it. He said the engine was full of water but that was OK because he had another engine he could put in it.
I contacted him one more time saying I did not understand how a thing could be so important that it would be necessary to deceive someone. I stated that I hoped I would not be in a position like that.
His response was I was making too big a deal out of it. He said that I did not need to know more about him. He said if he had asked about me I would have said it was none of his business. I even let this person into my bedroom to see my dogs. 
I know that he was not completely honest. He is the expert in automobiles and it feels like I was had! If he had been truthful I may have been a customer of his down the road. But with the experience I had that will never be. I still do not understand if a private party did not want to sell to a dealer, why not accept it and move on. Why turn to deceit to get what you want?