How would I genuinely convey that I want to help someone buy a car without sounding like a car salesman?

I have been selling cars for only 4 months now and I have been getting amazing results from being straight forward with people and helping them out. I love to help people, in fact, I actually got into the car business to pay for fire school because my ultimate goal is to be a firefighter. Firefighters only work two days a week here in Houston so I will need to have a second job to keep from getting stir crazy and I honestly think I could help people AND succeed if I continued to sell cars. My only issue is this... I get customers all the time that are liars and deceitful even when I am straight forward and honest with them. It seems like the kinder and more open I am with them, the more they take advantage of that. Its almost to a point that I don't believe a word anyone says anymore. I don't mind that people are rotten, but I think that even when people read my ads and here my offers to help them, they are unresponsive because they are expecting to be lied to. I would like to know of certain ways that I could advertise so that I can attract business and help people that deserve to be helped without sounding like one of those other idiots that are lying and cheating people and furthering the reputation of "the crooked car salesman". I have tried craigslist but it seems to be of no help. Even when my prices are posted right next to the other prices that are thousands higher, I am still getting zero responses. I work at "Planet Ford" here in Spring Texas, just north of Houston and I am at the top of the board this month. I have done so without being deceitful and I would love to make salesman of the month and show that it is possible to do while still retaining all of my morals. I have been in the oilfield my entire life and if you know anything about the oilfield, you'll know that its a "no bullshit" line of work. I would like to carry that same concept over into this business. I need to know where to advertise, how to advertise, when to advertise, etc... Any help would be greatly appreciated directly by myself and indirectly by those that I can help because of it. Thank you.