While I have the honor of meeting Patrick Renvoise, expert in neuromarketing, I completely agree with your statement: We are not what we promise, we are what we show. I do not intend in this post theorizing about neuromarketing, that's what the specialists. But the claim that titles this article deserves a reflection from the perspective of personal branding.
In any process of consulting personal branding there is only one thing beyond our control: Actually execution of an action plan. I can advise a person to write on a given topic to convince a certain audience. But I can not write about him; yes, I will perhaps early in the process, to cheer up, to demonstrate that writing is not so difficult. But writing, in the long run, would be devoid of authenticity, prove false.
When a large company president issues a speech, your personal brand is present. The same applies to a political leader; You can being advised, but in the end the speech has to chart its mark. Otherwise it will not be credible, at least in the medium term.
As much as we help someone to define its proposal, his message, eventually that promise needs to be demonstrated by card issuer. remember that, at the end, everything is known and masks just revealing what lies behind.
The conclusion can not be other: personal branding does not work miracles, in the end everyone has to be responsible for complying with the plan. A doctor can help you stop smoking, but can not make you stop smoking physically, that action up to you.