非誠勿擾 [－诚－扰]

Jyutping fei1 sing4 mat6 jiu5
Pinyin fēi chéng wù rǎo

Definitions (CC-CEDICT)
  1. serious inquiries only
Definitions (Wiktionary)
  1. phrase
    If you are not sincere then do not bother. / Serious inquiries only.