Before purchasing a used car, it is always wise to do some research of your own about the type of dealer you are planning to buy from. This can be done by checking with the Better Business Bureau, to see if there has been any form of complaints against this dealer. As a general rule of thumb, never fully trust the verbal promises of a used car dealer that might not even have evidence to back up.
Instead, it is better to hire a trusted independent mechanic to inspect the motor vehicle that you are planning to purchase. A significant red flag would be if the dealer refuses to let his vehicle be checked.