If one wants to succeed, then one should act as though one were genuinely confident about one's abilities, even if one actually distrusts one's skills.
Conclusion
If you want to succeed, you should act like you're genuinely confident in yourself, even if you're not.
Evidence
Success comes more easily to people who are genuinely confident than to people who are only faking it.
Evaluation
Sorry, what? Didn't the author just contradict himself? She said we should fake having genuine confidence, because people with genuine confidence do better than fakers.
She must be thinking that we'll fake it 'til we make it.
Goal
Look for an answer resolving this nearly contradictory advice. So long as we are fakers, we're going to have a harder time obtaining success, so this answer needs to get us from faker to a higher level of success.