Be Certain, But Be Prepared to Be Wrong
Huh!
Sounds like a big conflict– psycho mumbo jumbo.
What I mean is that if you are trading with an edge (a trade that has an expected winning outcome over a series of trades) then you must think that you will make a ton of money on the next trade.
You must expect to win.
So when a setup approaches, I try to remember a previous occasion when that same setup made a lot of money for me. I try to remember my initial apprehension that was finally rewarded by sticking with the trade.
On the other side of the coin, my money management requirements tells me that I must prepare for a losing trade. I need to use a stop.
Once that is taken care of I realize that I expect to win over time; just not every time.
That is the nature of trading with odds. They are never 100%; just like most things involving human behavior.
Get your mental edge in-line with your trading edge.