To be without some of the things you want is an indispensable part of happiness.
Tenderness contains an element of sadness. It is not the sadness of feeling sorry for yourself or feeling deprived, but it is a natural situation of fullness. You feel so full and rich, as if you were about to shed tears. Your eyes are full of tears, and the moment you blink, the tears will spill out of your eyes and roll down your cheeks. In order to be a good warrior, one has to feel this sad and tender heart.