Actually, I think your definition of 'best' isn't quite appropriate. Best is at best, a flexible definition, because you are not selling a product, but you are looking for a problem that your product can solve better than other ways.
We have many customers in our business: we are sure we're NOT the best school in the area for languages, but that is NOT what we sell our customers on. We sell them on our experience, our passion for teaching, our success in producing students who mostly will be able to use the language.
Moreover, we are trying to solve a number of other problems, as well. So our customers factor in a number of issues into making a decision: price, convenience, location, etc.. When there are so many factors, you cannot boil down the whole thing to just one factor.
If you just want to go shopping on a Saturday, would you buy a Ferrari or a Volvo? Which is better? If you want to race in Lemans, which would you buy then? If you want to go offroading, ... etc.. There isn't ONE answer to the question, which is the best car?
There is another reason: a customer's reason to buy your product may not always be the same as the reason you provide the product. You need to understand more about how your customers see you. Avoiding words like better, worse, etc. can avoid some of the moral complications.
Moreover, even if you don't make a sale, you can still 'educate' your customers on your product. That is an aspect that is seriously underrated. Even if they don't buy from you the first time, they will surely remember where they learned about the product. So do a good job teaching your customers, and they will learn to trust you. They will then likely buy from you at some point, if not today, perhaps tomorrow.
Just my 2c.
__________________ InvestorBlogger — So Blogging, Tech, and Making Money Can Go Hand-in-Hand