Although you may think you are sacred of failure, when you search deep within, you may fear succeeding.
Subconsciously you may feel that success is equal to more work, or a new routine that you are not ready for etc.
Usually when we think we fear something; it is not what we think we are scared of that we are actually scared of.
In the case of success, you know deep within that you are Powerful beyond measure and that may scare you.
The expectations would be through the roof if you succeeded at what you want.
There is so much that comes along with success, that usually it is not failure that people fear, but rising to their own greatness.