Themes
To love is to place our happiness in the happiness of another.
— Gottfried Wilhelm von Leibnitz

Behind the line May contain spoilers.
Our reading
An editorial interpretation.
Love, here, means your own happiness becomes tied up with someone else's. You feel good when they do. It's a definition that puts the other person's wellbeing at the centre, rather than describing love as a feeling that stays inside you.
Context reviewed