The title sets up a princess who walks away from the throne, and the poem seems to follow her thinking as she does it. It opens with a child's disbelief at how a king is made, as if power were a trick too strange to accept. From there the lines tilt toward doubt: the ambition to master everything turns out to leave you with nothing real to do, since "matters of the state" slide into "state of play," a mere game.
The sand image feels like the heart of it. The ground beneath us, the poem suggests, is shifting and finds "infinite fault" with whatever we build on it, so any kingdom looks shaky. Then comes the last line, which is surprising and calm: "I resolve to be the world." Rather than ruling things, she chooses to become part of them.
The mood is quiet, a little wry, and oddly freeing. It reads less like a loss than like someone setting down a heavy, slightly absurd burden.