μνῆστρον
From LSJ
κρείσσων ἐναρχόμενος βοηθῶν καρδίᾳ τοῦ ἐπαγγελλομένου καὶ εἰς ἐλπίδα ἄγοντος· δένδρον γὰρ ζωῆς ἐπιθυμία ἀγαθή (Proverbs 13.12 LXX) → One who sincerely sets about helping is better than one who makes promises leading to hope; for a kindly urge is a tree of life.
English (LSJ)
τό,
A betrothal, marriage, Cod.Just.1.17.3.ά, Charis. p.34 K.