At first i just tried to stay out of mitchell's way, but that didn't solve the problem. so i went to my sister, cassie, about mitchell. now, my sister was a beautiful girl and i knew even mitchell had eyes for her. but cassie was not only beautiful, she was tough, smart, and just a bit cocky. she was six years older than i was and pretty much like a mother hen when it came to me; i knew she'd take my part. "cassie, you know 'bout mitchell? " i asked her.

why does paul decide to talk to cassie about mitchell?

he knows that she will support him and give him good advice.
he knows that she will teach him how to win a fist fight.
he wants her to beat mitchell up for mistreating him.
he wants her to speak to mitchell about his bad behavior.