A male law student asked a girl in the university library, “Do you mind if I sit beside you?” 

The girl replied with a loud voice, “I DON’T WANT TO HAVE SEX WITH YOU!”
 
All of the students in the library started staring at the guy. He was embarrassed, and found another seat.

 After a couple of minutes, the girl walked quietly to the guy’s table and said, “I study psychology, and I know what a man is thinking. I guess you felt embarrassed, right?” 

The guy responded in a loud voice, “$500 FOR ONE NIGHT? THAT’S WAY TOO MUCH!”

All the people in the library looked at the girl in shock.

The guy whispered into her ear, “I study law, and I know how to make someone appear guilty.