ἐπιβεβαίωσις
From LSJ
Δεῖ τοὺς μὲν εἶναι δυστυχεῖς, τοὺς δ' εὐτυχεῖς → Aliis necesse est bene sit, aliis sit male → Die einen trifft das Unglück, andere das Glück
English (LSJ)
εως, ἡ, A further confirmation, Id.Rh.Al.1438b29 (pl.); guarantee, Sammelb. 5240.17 (i A.D.).
Greek (Liddell-Scott)
ἐπιβεβαίωσις: -εως, ἡ, ὡς καὶ νῦν, περαιτέρω βεβαίωσις, Ἀριστ. Ρητ. π. Ἀλ. 33, 1.