既来之，则安之

jì lái zhī , zé ān zhī

Since they have come, we should make them comfortable (idiom). Since we're here, take it easy.

Since this is so, we should accept it.; Now we have come, let's stay and take the rough with the smooth.; If you can't do anything to prevent it, you might as well sit back and enjoy it.

既

jì

already

来

lái

to come

之

zhī

(possessive particle, literary equivalent of 的[de5])

，

则

zé

(literary) (conjunction used to express contrast with a previous clause) but; then

安

ān

(bound form) calm; peaceful

之

zhī

(possessive particle, literary equivalent of 的[de5])