How can I get over it

everytime I like a girl I start hanging out with her talking to her more etc. but I never really have the guts to ask her out even if I know she likes me and is single so how can I get over that fear of asking

its not the fear of being rejected im just overall afraid to ask her out

You will never be able to get over a fear unless you face it. If she likes you then you should have nothing to worry about. And what is the worst thing that would happen? Her saying no? Also, if you really like her and she likes you, and you don't ask her out then you will regret it. So just ask.