ἀληθ-εύω · alēth-euō — LSJ
speak truth, speak truth, rightly foretold, prove, true
speak truth, A. Th. 562, Hp. Prog. 15, Pl. R. 589c; περί τι Id. Tht. 202b: with neut. Adj., ἀ. πάντα speak truth in all things, Batr. 14; πολλὰ ἀ. X. An. 4.4.15; τὰς δέκα ἡμέρας ἠλήθευσε he rightly foretold . . , ib. 5.6.18; ἀ. τοὺς ἐπαίνους prove their praises true, Luc. Ind. 20; τοὔνομα ‘make good’, Them. Or. 1.4c.
2 to be, prove true, to be fulfilled, arrive at truth, is in accordance with truth, to be truly predicated of
of things, to be, prove true, σημεῖα Hp. Prog. 25:—Pass., to be fulfilled, of conditions, ἐπὶ τούτοις -ομένοις X. Cyr. 4.6.10, freq. in Arist.:—Act. of reasoners, arrive at truth, Id. Metaph. 1062a25:—Pass., ὁ λόγος -εύεται is in accordance with truth, Top. 132b4, al.; ἀληθεύεσθαι κατά τινος to be truly predicated of . . , ib. 132a31, al.: fut. Med. in same sense, EN 1100a35, al.