Four short lines carry one simple, painful idea: being hurt once can make it hard to love again. The speaker doesn't describe who caused the pain or what happened. Instead, the poem goes straight to the result. If you find yourself unable to love, the speaker says, that is a sign you've been hurt before.
What stands out is the cycle the poem describes. The fear of being hurt again is what stops love from happening, so the old pain keeps shaping the present. The speaker seems to understand this from experience, or at least speaks with quiet certainty, as if giving a hard truth to someone else or reminding themselves.
The mood is sad and guarded, but also honest. The plain wording and the lack of decoration make it feel like a confession said out loud. There's no solution offered, only recognition, which may be the point: naming the fear is where understanding begins.