To get to the point where you can become fearless, you need to play really tight early game. Since fearless early game will get you to nowhere, since most of it is coinflips and people call you with ridicilous hands. When you get passed this moment, you can go on fearless mode. It will help you steal pots and bring your stack to another level. You gotta be lucky aswell , not to hit anything on the flop, but to be lucky enough so your opponent doesnt have a real hand to call you. You cant compare expert players with online gaming, since when pros play live its more of a chess game, than it is poker. They calculate, they take big chances and sometimes they are rewarded, sometimes not. But you cant do that online, because you will play against a player, who might be novice and not even noticing that you could have that flush or straight. They just call. I think that being fearless also mean that you push all in with pocket aces, knowing that you will most likely win, but there is a chance that this guy calls you with 2 7o and hits 2 pairs. Now a player thats not fearless wouldnt have played it this way, because he isnt watching the odds
to win, but the odds to lose. Everyone that cashes in a tournament has taken a few chances and got lucky ( to some point ) to get to there, so I think thats fearless.