I've been referred to as a "good girl," even though I tend to be rather perverse (derogatory terms really do not bother me much) and blunt (rarely do I lie) in conversation with close friends. I would have to think the term means that he shows respect for you... but doesn't really determine whether he has romantic feelings or you or not. It's just a compliment about your overall personality.
Most of my guy friends that wanted me romantically had asked me out... and those that didn't never asked me out. In either case... I was still referred to as being a 'good girl.'
"The weakest soul, knowing its own weakness, and believing this truth that strength can only be developed by effort and practice, will, thus believing, at once begin to exert itself, and, adding effort to effort, patience to patience, and strength to strength, will never cease to develop, and will at last grow divinely strong."
- James Allen