ἐν ἀπορρήτῳ λέγω

From LSJ

ἤτοι ἐμοὶ τρεῖς μὲν πολὺ φίλταταί εἰσι πόληες Ἄργός τε Σπάρτη τε καὶ εὐρυάγυια Μυκήνη → The three cities I love best are Argos, Sparta, and Mycenae of the broad streets

Source

Greek > English (Woodhouse)

inform confidentially, inform in strict confidence