If he had failed, he would have looked at the bright side, invented a new plan, and ran with it. You can plan ahead, you can have backups, but sometimes you can't look that far ahead--the best course of action is decided with the information you have at the moment, not what you decided a year ago. It's good to be adaptable.
Still, I wonder if he's confused. He says, "When you're confident, it's going to work, so believe it will." I think it's the other way around--if you know it's going to work, that makes you confident, and then it works (because it was a good plan, not because you were confident).
Enterprising involves a great deal of risk. Without taking risks, all businesses will fail. The founding of a business is a risk by itself, considering initial investment and time spent organizing and marketing.
If you hesitate too long to implement a good plan (i.e. you are not confident), you will fail. If you believe strongly in a bad plan, you might fail. Very strange things have become very popular (pet rocks come to mind), and unlikely businessmen have managed to succeed (Subway comes to mind).
"Confidence" may be a synonym for "calculated recklessness" here. Although this action may fail, its benefit outweighs that risk.
Every plan requires energy, and sometimes it's more effective to perfect "Plan A" than to strengthen Plan B. When Plan A succeeds, the work on Plan B won't matter.