Love is an identical vibration to appreciation. And appreciation is nothing more than positively focusing towards something.  This means that unconditional love is the same as unconditional positive focus.  A simpler way of putting this is that unconditional love is positive focus (appreciation) that is not conditional upon how another person acts.  Now it is time to get real for a minute.  How many of us on this earth are capable of that right now?  Not many of us.  And this should not make you feel bad about yourself because unconditional love and enlightenment are the exact same state.  We know how difficult it is to reach enlightenment.  It is a lifelong practice if not a multi lifetime practice for most beings.  And we also know that enlightenment is not a goal that we reach.  Instead, it is a horizon line that continues to move further into the future with every desire that we have and with every new perspective that we are introduced to.  It is the same with unconditional love.  Unconditional love is a practice, it is not a state we achieve and are then done practicing.  There is no retirement from the practice of unconditional love.