οὐ μὲν οὖν
From LSJ
Ubi idem et maximus et honestissimus amor est, aliquando praestat morte jungi, quam vita distrahi → Where indeed the greatest and most honourable love exists, it is much better to be joined by death, than separated by life.
English (LSJ)
or οὐμενοῦν, A on the contrary… not... introducing a neg. statement in contradiction or correction of a preceding statement or suggestion, Ar.Pl.870, Ra.556, 1188 οὐδενὸς μὲν οὖν ἄξιον Pl.Euthd. 305a; ἐγώ σοι οὐκ ἂν δυναίμην ἀντιλέγειν; Answ. οὐ μὲν οὖν τῇ ἀληθείᾳ δύνασαι ἀντιλέγειν nay it is not me, but rather truth, that you cannot gainsay, Id.Smp.201c, cf. D.18.140:—so οὐμενοῦν… γε, Paus.1.20.1; v. μέν B. 11.2.