I'll be a nun!

That's was I overheard some teens said out loud. It made me think of a scenario that I'm very sure had happened.
A girl trying to push her boyfriend to marry her and use those words to push his hand. Or a young girl saying to a young boy so he would agree to go "steady" with her.
I really wonder.. Why the girls are so desperate to be in a relationship with a guy who is unsure? And why the guys feel bound to follow the girl's wishes?
It will never turn out well for both parties. The girl will continue to demand more and the guys will feel lost in what to do. Never step into a relationship until both are sure in their feelings for each other. There is no point to cling on to someone who is not ready to commit.