ἔσσεται

From LSJ

ψυχῆς ἀγῶνα τὸν προκείμενον πέρι δώσων → to stand the appointed trial for his life, to stand the appointed struggle for life and death

Source

French (Bailly abrégé)

p. élis. ἔσσετ’;
3ᵉ sg. fut. épq. de εἰμί.

Russian (Dvoretsky)

ἔσσεται: эп. = ἐσσεῖται.