Frank Herbert, the author of Dune has a mantra called the Shai-Hulud and goes.
I must not fear.
Fear is the mind-killer.
Fear is the little death that brings total obliteration.
I will face my fear.
I will permit it to pass over me and through me.
And when it is gone past me I will turn to see fear’s path.
Where the fear has gone there will be nothing.
Only I will remain
Such self-talk may help characters in a book and it might not hurt us either but I believe that fears must be dealt with in the power and with the presence of God.