you cant make sure - if your girlfriend feels that you are too suspicious, jealous or controlling, it might cause her to leave you in the first place.
obviously, she doesnt love you anymore so you should just leave her alone.
you hog-tie her.
i reccommend that you re-write this question, becausse it doesnt make sense.
If she is your EX girlfriend, the she is nothing to do with you any more, do as she asks LEAVE HER ALONE to make a new life without you.
make him jealous. let him see what he's missing in what he claims he didnt want.
Curiousity of not seeing you make her not to talk much...
You shouldn't do that unless they are bad for each other.
That probably means she is trying to make your girlfriend jealous...Maybe. It depends on what kind of person she is.
focus on your own happiness instead-leave her to get on with her life.
Tell your brother about it. Tell her that his girlfriend makes you uncomfortable. if this doesnt work, try to make your brother look bad so shell break up with him.
Simple, make her jealous. Cooobra : she doesnt even care :( ive tried that...
make an effort. ask her on a really romantic date. if she still doesn't then ASK HER!