IMO insecurities are pretty much the same as fears, but on a different level.
For instance, a fear of rejection by others is also social anxiety.
Therefor, I believe it is best to face these things head on. Forcing oneself to do what is fearful or uncomfortable has a double benefit. One can overcome their fears and gain an immense sense of pride and self worth by doing so.
Allowing one's fears to control one's life is hardly living.
Just think of an insecurity it could be physical like if you don't like one of your facial features or it could be something thats indicative to social Anxiety, somwthing that could cause you to be overwhelming shy or jealous. Something like that.