Option 1 -> A pacifist opposes violence and war, which doesn't directly relate to idealism about life in general.
Option 2 -> An optimist maintains hopeful and positive views, perfectly aligning with die-hard idealism towards life.
Option 3 -> A skeptic questions and doubts beliefs, which contradicts having strong idealism.
Option 4 -> A pessimist expects negative outcomes, the complete opposite of idealism.
Hence, Option 2: optimist -> Die-hard idealism reflects unwavering belief in positive principles and values, which is the hallmark trait of an optimistic person who maintains confidence and hope about life -> correct