A common reason linked to the fear of confrontation is the fear of rejection. This is helpful because if someone understands why they are afraid of something it can help them to overcome it. Everyone has been rejected in some form or fashion in their lives but for some people the rejections were more public or impactful than others. After some contemplation, if you think your fear of confrontation is linked to fear of being rejected, focus on such positive things as “it’s OK to be rejected sometimes; nobody gets along with everybody,” or “mental or emotional discomfort will pass, especially if you know you handled the confrontation to the best of your ability.”
Related to that last bit, guilt can make overcoming a fear of confrontation even harder; guilt about being “too mean” or “not reasonable” enough, etc. A common frame among experts is to approach the confrontation with a kind, yet direct demeanor. Remember to keep control of yourself at all times, even if it means slowing down the pace of communication to make sure you don’t do or say anything that will come back to haunt you. People frequently feel guilty about making mistakes in general; that guilt is amplified when they make a mistake during a confrontation and after enough mistakes start to build up a fear of confrontation in general. Be your best self and you have nothing to feel guilty about.
Lastly, listening will go a long way to make any confrontation more productive. The worst type of confrontation is one where nothing was accomplished at all because odds are the issue will still need to be addressed, which sets the stage for another confrontation. When both people listen to each other, or let each other know when they feel like the other is not listening to them, it increases the odds of resolving the issue the first go around.