I had a coworker who had a friend who worked at an ad agency. It seems that people don't generally advertise the things that are generally true. They usually advertise to make up for a real deficiency. OP it seems that you were the victim of misleading advertising about your slob roommate. They were probably glad to get him out of their home... There is no good way to cure someone of laziness except to have them face the consequences of their behavior. Sadly I don't know how you are going to do that without ultimately evicting the slob.

This problem won't fix itself. You're going to need to sit down and talk to your roommate. He's probably going to feel attacked and freak out so make sure you approach it in a careful way. Be sure to cite specific times and specific issues. Try to cite three if possible. You could try reading a book called crucial conversations before you do this.

A little late to say this, but if people have to constantly emphasize something, it's usually a lie