The reality of love and kindness is that they are similar, but not the same thing.

For kindness is a necessary component of love. But kindness is not love.

Maybe one could draw it out by saying:

Kindness + Devotion + Relationship + Grace = Love

You are kind to the lady in line at the store, but this speaks little to how you are kind to your children.

I might, indeed, have learned, even from the poets, that Love is something more stern and splendid than mere kindness: that even the love between the sexes is, as in Dante, ‘a lord of terrible aspect’. There is kindness in Love: but Love and kindness are not coterminous, and when kindness (in the sense given above) is separated from the other elements of Love, it involves a certain fundamental indifference to its object, and even something like contempt of it.

-C.S. Lewis, The Problem Of Pain (Amazon)