Ζῆν οὐκ ἄξιος, ὅτῳ μηδὲ εἷς ἐστι χρηστὸς φίλος → Life is not worth living if you do not have at least one friend.
adj.
Genuine: P. ἀληθινός.
Of character: P. and V. ἁπλοῦς, Ar. and P. ἄδολος.
Free from falsehood: P. and V. ἀψευδής (Plat.).
sincērē: adv., v. sincerus.