I'm afraid to talk to my best friend
Why would you be afraid to talk to a best friend?
I am not brave enough to tell them how I feel about them personally.
You shouldn't be in a relationship where you are afraid to tell them how you really feel. You will just be miserable when you hangout with them.
I can't end the friendship. They will be so sad if I do that.
If you feel a certain way about them than you have no choice but to tell them. While it may be difficult, just know that there needs to be honesty in relationships for them to work out long term. People go through way to many emotions in life to not share them!