If you put your full trust in God and since he is all love and all-knowing, you should never need to worry, be anxious, or afraid anymore. This is the theory that sounds totally logical and I can't find any flaw in it either. Therefore, put it into practice and become confident, bold, and fearless.
A footnote. This is not to say that you'll no longer experience any agony or have sufferings or crosses to bear. The difference is that now you will have the strength and inner peace to deal with anything that comes your way.