By the way the entire riddle goes:
What is greater than God
More evil than the devil
Rich people need it
Poor people have it
if you eat it you will die
what is it ?
Supposedly like 5% of Harvard graduates got it right, but 97% of kindergarteners did.
I love riddles!
I think the hard one the answer is the man is married to her estranged twin sister, and by killing her sister she has the man to herself by pretending to be her twin.
Gale