此男已有妻请勿勾引此女已有夫请勿调戏
[cĭ nán yĭ yŏu qī qĭng wù gōu yĭn cĭ nǚ yĭ yŏu fū qĭng wù diào xì]
This translates to: This man already has a wife, please do not tempt him; this woman is already married, please do not tease her. It warns others against getting involved with individuals who are committed.