Joy is not the same as happiness. Happiness depends more on circumstances, it comes and goes with the weather of our lives. Joy is something more stubborn. It can coexist with grief, with uncertainty, with loss. It doesn't require everything to be fine.
And yet it can be surprisingly hard to reach. Especially for people who care intensely, who take the world seriously. Seriousness and joy aren't opposites -but they can crowd each other out.
Maybe that's what longing for joy really means: not the absence of difficulty, but the ability to find something luminous in the middle of it. To laugh. To let go, just for a moment, of the burden of caring.