How do you know she's the one?

I have been hooking up with women for years. More commonly, I hook up with Colombian women since I am currently living in Colombia. I get into a serious relationship sometimes but I just couldn't find myself settling down with these women until I met this girl. She's gorgeous beyond doubt and words, trust me. We started dating in a short period of time and although it was only just for fun, my feelings started getting real. I just am not sure if I should be feeling this way toward her. How do I know if she is the one or not?