Lewis & Short

sīcĭnē (less correctly, siccĭne), adv. [sice, orig. form of sic, q. v., and the interrog. particle ne], so, thus; in interrog. and exclamatory sentences always beginning the sentence (once in Cic.; twice in Liv.; not in Cæs. or Sall.; freq. in the comic writers; sometimes in the other poets). Like sic, it refers either to a previous statement, or δεικτικῶς to something pointed out by the speaker (cf. sic, I. and III.). It almost always implies reproach; sometimes self-reproach (v. infra, 3.).

    1. 1. Referring to a previous statement: Sicine mi abs te refertur gratia? Plaut. Ps. 1, 3, 101: Sicine me spernis? id. Rud. 3, 6, 46: Sicine agis? Ter. Eun. 1, 2, 19; so id. ib. 4, 7, 34; id. Ad. 1, 2, 48: Sicine hunc decipis? id. Phorm. 3, 2, 43: Sicine tu eum, cui tu in consilio fuisses … in discrimen vocavisti? Cic. Fl. 33, 82: Sicine vestrum militem sinitis vexari ab inimicis? Liv. 6, 16, 2.
      So in oblique discourse: Rogitansque, sicine pugnaturos milites spopondisset? Liv. 7, 15, 2; cf. Plaut. As. 1, 2, 1; id. Cist. 2, 3, 38; id. Merc. 1, 2, 49; id. Poen. 1, 2, 176; Ter. Heaut. 4, 3, 13; Cat. 64, 132; 64, 134; 77, 3; Sil. 9, 25.
      Rarely used predicatively: Sicine est sententia? Ter. Heaut. 1, 1, 114.
    2. 2. Referring to something pointed out: Sicine hic cum uvidā veste grassabimur? Plaut. Rud. 1, 4, 32: Sicine, lente, jaces? Prop. 3, 7 (2, 15), 8; cf. Plaut. Cist. 1, 1, 115; id. Ps. 5, 5, 1; id. Poen. 3, 1, 9; App. M. 9, p. 180.
    3. 3. Sometimes it introduces exclamatory infinitive clauses: Sicine mi esse os oblĭtum, O that my face (eyes) should have been thus covered (blinded), Plaut. Curc. 4, 4, 34: Sicine me atque illam operā tuā nunc miseros sollicitarier! Ter. And. 4, 2, 6; cf. Plaut. Pers. 1, 1, 44.
    4. 4. Very rarely without implying reproach: Sicine eam incomptis vidisti flere capillis? did you see her weep just as she was, with unkempt hair? Prop. 4, 5 (3, 6), 9 (cf. sic, V. 3.).