Prince is greedy and wants more, and works for true misery.
This does *not* include giving up his riches -- that he cannot bring himself to do -- this has the ironic effect of making him so profoundly miserable that he is the most unhappy man on earth.
He fears torments of hell if he is happy in this life.
Yet on deathbed, realizing at last that he has achieved goal of absolute misery, he has a surge of great joy, dies happy.