Lyrics:

Don Raye / Gene DePaulYou don't know what love isUntil you've learned the meaning of the bluesUntil you've loved a love you've had to loseYou don't know what love isYou don't know how lips hurtUntil you've kissed and had to pay the costUntil you've flipped your heart and you have lostYou don't know what love is

Billie Holiday You Don't Know What Love Is