In his work, Harry Frankfurt uses 'caring' and 'loving' as two separate things. But what is the difference between the two?
See : Harry Frankfurt, The Reasons of Love, Princeton University Press (2006), page 11:
to say that there is something we care about, or — in a phrase that I shall employ (perhaps a bit willfully) as closely equivalent to this — something we regard as important to ourselves. In certain cases, moreover, what moves us is an especially notable variant of caring: namely, love.
And page 16:
Besides wanting to fulfill his desire, then, the person who cares about what he desires wants something else as well: he wants the desire to be sustained. Moreover, this desire for his desire to be sustained is not a merely ephemeral inclination. It is not transient or adventitious. It is a desire with which the person identifies himself, and which he accepts as expressing what he really wants.
Thus, to care of implies reasons and projectuality, more than simple desire.
And page 23:
The totality of the various things that a person cares about — together with his ordering of how important to him they are — effectively specifies his answer to the question of how to live.
See page 29:
The commands to which they do in fact respond [when people commits to the well-being of their children] are grounded in a source that is constituted not by judgments and reasons, but by a particular mode of caring about things. They are commands of love.
See page 31:
So far I have characterized what I refer to as “love” only as a particular mode of caring.
And finally, page 37:
Loving someone or something essentially means or consists in, among other things, taking its interests as reasons for acting to serve those interests. Love is itself, for the lover, a source of reasons. It creates the reasons by which his acts of loving concern and devotion are inspired.
Thus, love is by itself the reason for care about someone.