You can only trust yourself. Maybe I'm paranoid, of course, but trusting other people is quite dangerous, and often this risk does not justify itself.
You can trust yourself the most when your trading knowledge and strategy seem effective. Because if you don't have trading skills, trusting yourself will not get proper results, but more opposite results may come. A trader often needs to follow different traders to develop his trading strategy and prepare himself better by analyzing their activities.
So if you want to fully trust yourself, you have to build up your trading skills and develop the ability to understand the market.