Opening up to someone you don't know can feel easier than opening up to anyone close, and that's the simple idea at the heart of this short poem. The speaker admits that sharing secrets and worries with a stranger brings a kind of relief, and they can't quite explain why. The word "somehow" appears at the start and again in the middle, as if the speaker is still puzzling it out.
The repetition does a lot of the work. Each section follows the same pattern: the speaker confides, then repeats "a stranger, a complete stranger," almost like a refrain. That insistence suggests the anonymity is the whole point. A stranger has no history with the speaker and may not judge or remember. The results build gently, from "gratifying" to "calms" to "makes it hurt less," so the relief deepens.
The mood is quiet, tender and a little lonely. There's comfort here, but also a hint that safe listeners are hard to find.