I can try: As far as I can see, a good sales person sees the needs of the customer and presents the product in such a way that it is clear to the customer that

I can try: As far as I can see, a good sales person sees the needs of the customer and presents the product in such a way that it is clear to the customer that it will fulfill a need. Or, in other words, a B2B salesperson's job is to say "buying our product will offer a very good return on investment" in a way that sounds true to the customer. This requires some knowledge of the product, but it requires far more knowledge about the customer, their line of business, what people make purchasing decisions etc.