Someone who fears death will never live like a truly alive person. But someone who accepts that death was their fate from the moment they were born will live according to that truth. This mindset gives them a bonus: nothing can catch them off guard. By imagining that everything bad that could happen will happen to them, they remove the shock from all troubles. Bad things can't hurt people who expect them and are ready for them. Trouble only hits hard when it surprises people who never thought about it — people who only focused on being happy.
He who fears death will never act as becomes a living man: but he who knows that this fate was laid upon him as soon as he was conceived will live according to it, and by this strength of mind will gain this further advantage, that nothing can befal him unexpectedly: for by looking forward to everything which can happen as though it would happen to him, he takes the sting out of all evils, which can make no difference to those who expect it and are prepared to meet it: evil only comes hard upon those who have lived without giving it a thought and whose attention has been exclusively directed to happiness.