When a salesperson has no knowledge about a product or service sold and the buyer is interested in a product or service, as it may cause the bout did not succeed and make the seller is not ensured.
When a salesperson has no knowledge about the products or services they sell and buyers are very interested in your product or service is grilled, it may not be successful and the seller is not assured.
When the salesman who is knowledgeable about the products or services they sell and buyers are interested in the product or service is as much it may not be a success, and make the seller is not sure.