Action creates evidence. The people that take action does not mean they are confident, instead they use the results of their action to build confidence to act even more. The people who have the fear are people who are not taking the first step of faith and they dont know that confidence is built when you take that first step.
Most people that have fear of the unknown dont have the confidence in themselves hence they are not taking action. The step of action makes you realise that all this time you have the confidence within yourself you just needed to unlock it with your action to see how much confidence you have. Action even unlocks the fears of doubt you had towards something, or doubts you had even in yourself. I remember after publishing my first book the confidence I had afterwards because I never knew that I could be an author until I stepped into it and took action about the work that I built for years writing daily. Today I see myself publishing more books and helping others identify their gifts because I realised mine. As a result, the confidence i gained from publishing my first book gave me the confidence to start and act on other things that are today a success. And it all started with just a step of action in what i believed in and that changed my life for the best. Action unlocks what seemed so impossible. It gets to show that indeed whatever you act on turns into a blessing. We carry blessings within ourselves and we just need to take action and see the blessings flow from us and turn things to success.
I dont know what is holding you back. I dont know what you need to take the step of faith. You dont need motivation to build confidence, you need to take action to build confidence. Take that first step and confidence will automatically follow.