Fear – Traders become fearful of entering the market usually when they are new to trading and have not yet mastered an effective trading strategy like price action trading (in which case they should not be trading real money yet anyways). Fear can also arise in a trader after they hit a series of losing trades or after suffering a loss larger than what they are emotionally capable of absorbing. To conquer fear of the market, you primarily have to make sure you are never risking more money than you are totally OK with losing on a trade. If you are totally OK with losing the amount of money you have at risk, there is nothing to fear. Fear can be a very limiting emotion to a trader because it can make them miss out on good trading opportunities.
However, being able to push this fear aside and work through it is absolutely vital for any trader who wants to be successful. Practice trading, make notes, research new strategies and make mistakes. Trial and error is a massive part of the Forex learning curve, and generations of traders have proved that this is the most effective way to eliminate trading fears.
The problem is that this is where traders are most likely to succumb to overconfidence bias. It's not uncommon for traders to complete a winning streak and then believe that they can't get anything wrong in the future. To believe this is of course unwise, and is only going to end in failure. Make sure you always analyse your trading sessions and look at your wins and losses in detail.