Trust is the only way I suppose, I thought my girlfriend loved me, we were perfect, but at my age girls just get "bored" of their boyfriends, and she eventualy cheated on me last week. I feel as if im to mature for relationships my age lol.
there is no test
you should just know
and if you dont than maybe you should not be with that person
If they love you then you will know really you will!
By asking the very question and seeking and needing proof means you have your doubts so the question is really DO YOU LOVE THEM?
Maybe you are too insecure and needy to form real loving relationship?
Lock her/him and your dog in the boot of a car for an hour and see which one is happiest to see you when you open it!
The question is.. if you truly love them, should you be "testing" them?
You don't test people you love or who love you.