A man can aim so high that even death cannot corner him. He orders his whole being toward embodying the ideal. Once that is his purpose, the outcome loses its power to shame him, because whatever happens becomes another chance to make the ideal visible. Life would serve it. Death would serve it too. The aim swallows the alternatives whole.
Boldness of this kind is not bravado. It grows from having something to live for that is larger than staying alive, so that the fear of ending stops being the thing that runs him. He wants the highest good magnified through his own flesh, in his conduct, in how he meets the end. Give yourself entirely to what is worth serving, and the terror of dying has nowhere left to grip.