Well I guess, I just need a liite help to figure out this girl,how could I tell the difference betewn an a good girl(not a player or cheater or easy)who is a flirty or a player?

Time.

Take the time to get to know her. Hang out together at social events. Talk to her.

You would have to get to know them.
Do not rely on what others have told you.
Judge for yourself ,if you must judge at all.

The relationship type girls are the ones who have nothing to hide.. don't check her messages or try to get to know facts about her older sexual activity. Instead try to convince her that your a right guy by your actions. Don't be afraid to reveal some of your feelings towards her like admiration and enthousiasm but still.. don't go to deep. Have some time together.. sooner or later you will (even partially) analyse aspects of her personality for sure