ㄌㄞˊㄓㄜˇㄅㄨˊㄕㄢˋláizhě‑búshànㄕㄢˋㄓㄜˇㄅㄨˋㄌㄞˊshànzhě‑bùlái

来者不善,善者不来
láizhě‑bùshàn, shànzhě‑bùláiㄌㄞˊ ㄓㄜˇ ㄅㄨˋ ㄕㄢˋ,ㄕㄢˋ ㄓㄜˇ ㄅㄨˋ ㄌㄞˊ
  1. 好意好意不會 來者不善,善者不來小心對付」。

He who comes is surely ill-intentioned, no-one well-meaning will come (idiom)​., Be careful not to trust foreigners., Beware of Greeks bearing gifts!