Love is a subjective measurement of one of the four primary resources of civilization, Trust. The other three resources are Capital, Information and Inspiration.

If you love someone, you are giving them a positive value for whether you trust them or not. You can describe love as 100% trust, or anything positive compared to where you see someone else on the same spectrum. You can love one person more than another, because you trust them more. You can love a sunrise more than a rainy day, or you can love how something or someone makes you feel, because you trust that the memory of that feeling is something you can bring back at any time, or get back again and again with the same person or the same experience.

If you lose trust in someone, due to betrayal or a mistake, you can say that you love them less, or that you no longer love them at all. And if someone earns your trust sufficiently, you can mutually agree to spend the rest of your life with them, trading a ring for a lifetime of memories.