The paragraph is followed by an incomplete phrase or sentence which summarizes the main idea of the paragraph. Choose the missing words of the phrase or sentence.

The relationship between a sales person and a client is important as both parties want to feel satisfied with their deal and neither wants to feel cheated. A sales person should believe that his product has certain advantage over the competition. A customer wants to be sure that he is buying a product that is of good value and high quality.
（） benefit of business deals.