Complex sentence: Roarke is one of the richest men on or off the planet, if not the richest, he owns one third of the planet and its satellites; however, Dallas isn't entirely comfortable with the great amounts of cash he has.
Split into simpler sentences: Roarke is one of the richest men on or off the planet, if not "the" richest; he owns one third of the planet and its satellites. However, Dallas isn't entirely comfortable with the great amounts of cash he has.