Good branding will make a customer believe your pitch, but great branding will make the promise come true. You can advertise that your product will make you more attractive, make you more respected socially and an all around better person; but expert branding speaks to a customer in such a way that deep down they just know having what you sell will give them those things.
It is not enough that your customers believe your branding; you must believe it as well. This will inspire you; and working from your inspiration you can create a brand that has longevity, loyalty and life.