Is it true that if a girl goes after a guy long and persistent enough, he'll eventually give in?

I saw this funny Korean movie "Please Teach Me English" and there a was a very plain girl who liked a flashy guy. The guy was so uninterested in her but she just followed him relentlessly. After 3 months, he gave in, started dating and later married. I'm a girl and whenever I show interest in a guy, he reciprocates but no matter how long a guy I don't like follows me, it's not going to happen. Is it true that guys have a weak spot for girls that like them? Eventually, they will give in???