[YoungGunner]

My thought has always been that actions speak louder than words. If she flakes on you/ acts rude flirt with other girls in front of her to make sure she knows her place. If you do decide to call her out after she really has crossed the line and jealousy/ coldness won't do the trick, don't pull any punches, think of a parent scolding their insolent child and then cutting off all contact from them.