“ When you feel someone else's pain and joy as powerfully as if it were your own, then you know you really loved them. ”
Source: Girls in Pants: The Third Summer of the Sisterhood
Similar Quotes
Love is not a joy; it is a deep, wonderful pain. Everything within you should tear. Only then will you know what love is. 
If tears of love, joy, and ecstasy have not washed your cheeks, you are yet to taste life. 
The most painful thing is losing yourself in the process of loving someone too much, and forgetting that you are special too. 
If you see both "pain" and "beauty" of Life, then there would be enormous compassion in you, and yet no pain in you. There would be joy in you even though there is so much misery. 
L'amor che move il sole e l'altre stelle. It means that love is the most powerful force in the world. That love can do anything. 