Many times, deals are lost due to trust issues with the customer. This can be from a variety of reasons. It may be that the customer had a bad experience with a previous representative. Maybe they were lied to. Maybe they were scammed out of money. Whatever the reason, it can certainly be overcome by a little bit of persistence and quite a bit of rapport.
Don't just be a sales person, be a product specialist. Better yet, be an industry guru! Show that you're knowledgeable and that you know the product that you're offering to them.
Let them know that you'll be their representative for a lifetime. If they like you, this could close the deal. If they don't like you, they weren't going to buy from you anyways.