Nemo figured that he just needed prove to himself that Sarah Beth was just another girl. But how? Maybe if he spent more time with her, he would realize that she was all wrong for him and then he could move on with his life. The thought of spending time with her made him smile.
Nemo knew that he couldn't just walk up to her and ask her out, he had to take it one step at a time. He had to get her to trust him again.