Selling groceries in a supermarket can be perceived as being significantly easier than selling used cars.
There are some things in common with both: the consumer or prospect has a need and walks into the store or on the lot, but the difference is price and signing things on the dotted line at the car dealership, which is why it is imperative for salespersons to build bridges right at the start and not force a sale. A forced sale can ruin a sales career, which is why any salesperson should assume to some extent and treat selling cars to selling groceries, with a no pressure, relationship building approach that will get them started and build throughout your tenure as a rep.
Be kind, courteous and knowledgeable about what you sell. Educate and not infuriate your prospects.