Honesty is the most single most important factor having a direct bearing on the final success of an individual, corporation, or product.

This quote means that being honest is the most important factor when it comes to being successful. If someone, an organization, or a product is honest and does not have any dishonesty or shady practices, then it will be successful in the long run and people will trust it. Honesty is the foundation for success, and any lack of honesty will lead to failure.