Yes, it's true. 100%.
It's not difficult to do and it doesn't require a super-skewed R:R (no 1 tick winners with huge stops!).
What I'm talking about is +ve Expectancy.
If amateurs make money on any one trade, they get excited, elated and pumped up. If they lose, they may question what they did wrong, get depressed and downtrodden.
Professional traders think differently. They learned that as long as they stick to the proven plan, EVERY trade they take has a +ve E and, therefore, is a winner...even if the single event loses.
Good days and bad days are now no longer synonymous with winning days and losing days. They wake up one day and chuckle to themselves when they realise that they were more upset about that day when they made $200 (whilst deviating from the plan) than the day where they hit their $300 daily stop (whilst taking every valid trade and managing them perfectly according to their plan).
Outcomes are meaningless in the short-term. Following the proven plan 100% of the time means you are ALWAYS winning (even when you are losing).