For myself, I can only say what love is from my stance as an existentialist. I cannot measure or delineate its nature and essence, nor can I distinguish it in absolute terms from what it is not. I can only say that the fact of love's existence is of higher import than its essence. That it is, is of greater significance to me than what it is. Love is an investment of the heart in what is estimated to be of highest value.
Love is the recognition and claiming of one's reflection and one's complement.
Love is the bond that gives answer to one's yearning for connection, gives whatever release there may be from the void of isolation. Love is the imperfect striving of the imperfect person to achieve the impossible-perfect union. Love is what gives rise to grief when love or the beloved is absent or dead. Love is what gives rise to despair when that which is loved absolutely, is absolutely inaccessible. Love is what gives rise to indignation when the beloved is wronged.