a great salesperson will never be selling something that they don't believe actually helps the customer
This seems very much like a No True Scotsman fallacy.
This seems very much like a No True Scotsman fallacy.
There are great salespeople the world over selling products they don't believe in — after all, great products tend to sell themselves — but you can bet your bottom dollar they'd be doing an even better job if they did believe in the product.
Self-delusion is a powerful force, but smart people need more than that to achieve any kind of lasting result.
I guess it will depend on what the product being sold is, enterprise software is probably somewhat different to timeshares or double glazing.
It is worth bearing in mind though that some of the best salesmen throughout history have probably been people who were knowingly selling scams.