Parsing inflected forms may not always work as expected. If the following does not give the correct word, try Latin Words or Perseus.
fortasse-an (sometimes written separately fortasse an), adv. [cf.: forsan, forsitan, fortan], perhaps, perchance (ante- and post-class.): fortassean sit, quos hic non mertet metus, Att. ap. Non. 138, 33; Sisenn. ib. 82, 6: de fructo, inquit, hoc dico, quod fortassean tibi satis sit, Varr. R. R. 3, 16, 10; 3, 6, 1: fortasse an pantherae quoque et leones non Africae bestiae dicerentur, id. L. L. 7, § 40 Müll.: fortassean dixerit, etc., Gell. 11, 9, 1: ea omnia comtius fortasse an dici potuerunt, fortius potuisse dici non videntur, id. 7, 3 fin.; 19, 8, 6.