πεποιθέναι
From LSJ
Ὁ δὲ μὴ δυνάμενος κοινωνεῖν ἢ μηδὲν δεόμενος δι' αὐτάρκειαν οὐθὲν μέρος πόλεως, ὥστε ἢ θηρίον ἢ θεός → Whoever is incapable of associating, or has no need to because of self-sufficiency, is no part of a state; so he is either a beast or a god
Greek > English (Woodhouse Verbs Reversed)
(see also πείθω): be certain, be convinced, be positive, be sure
