Everything in Robert Kern's poem hinges on one small word. "This" is never explained. We don't learn what the speaker believes about the world, only that they believe it, and that the world offers nothing to back it up. That blank is the point. It lets us fill the gap with our own private conviction, whether it's about faith, hope, love, or something we can't quite name.
The speaker sounds caught between stubbornness and doubt. "Must I discard this?" is a real question, asked without much hope of an answer. The last two lines land the dilemma neatly: the belief is "driving me crazy" and also "keeps me sane." It hurts and it steadies at the same moment.
The mood is quiet, wry, and a little weary. The plain, short sentences feel like someone thinking aloud, admitting that a belief doesn't need proof to matter, even when it costs them.