此男有妻请勿勾引此女有夫请勿搭讪
[cĭ nán yŏu qī qĭng wù gōu yĭn cĭ nǚ yŏu fū qĭng wù dā shàn]
The phrase translates into 'This man has a wife, please do not tempt. This woman has a husband, please do not flirt.' Expressing commitment, boundaries, and respect in relationships.