Real love means service devoted to the welfare of another person, even if the person is inimical towards us. That is the test of love.
If one has real love, only then can he be grateful and appreciate another.
Real love is expressed through service. A mother is willing to do anything and everything to serve the child. She is willing to stay up late in the night, willing to clean all the mess that the child creates and willing to sacrifice her very life for the child. That is service.