Don't make it sound like she can manipulate you. Just ask her how serious she is about you, like would she want to get engaged. If her answer is "yes" that means she wants you to stay around. Usually I support direct communication but your wording made you sound desperate, and opens the door to girls manipulating you, even when they aren't sure what they want.
I have a long time interest in psychology, specializing in relationship dynamics for 30 years.
(Please note, we give the best advice we can based on the information given in a post. For better advice, please include the age of all romantic partners.)