How can you tell if the nonfiction you are reading contains opinion?

1: headings will indicate any use of opinion

2: only fiction makes use of opinion in writing

3: there will be signal words and phrases

4: it is best to write to the author to find out

judy jones is an attractive woman who receives attention from many men throughout the story.   despite her beautiful appearance, she is superficial and callous.   she is an aggressive woman who goes after any man she desires but she is not happy.   she is fickle and is never satisfied.   her beauty is only skin deep.   dexter breaks down because he knows his dreams are unattainable.   he believes that wealth and physical beauty are what will make him happy.   he soon realizes that she has lost her attractive looks.   it is not all what he had planned.