Quīn is especially common with nōn dubitō , I do not doubt , nōn est dubium , there is no doubt , and similar expressions:— nōn dubitābat quīn eī crēderēmus (Att. 6.2.3) , he did not doubt that we believed him. illud cavē dubitēs quīn ego omnia faciam (Fam. 5.20.6) , do not doubt that I will do all. quis īgnōrat quīn tria Graecōrum genera sint (Flacc. 64) , who is ignorant that there are three races of Greeks? nōn erat dubium quīn Helvētiī plūrimum possent (cf. B. G. 1.3 ), there was no doubt that the Helvetians were most powerful. neque Caesarem fefellit quīn ab iīs cohortibus initium victōriae orīrētur (B. C. 3.94) , and it did not escape Cæsar's notice that the beginning of the victory came from those cohorts. Dubitō without a negative is regularly followed by an Indirect Question; so sometimes nōn dubitō and the like:— nōn nūllī dubitant an per Sardiniam veniat (Fam. 9.7) , some doubt whether he is coming through Sardinia. dubitāte, sī potestis, ā quō sit Sex. Rōscius occīsus (Rosc. Am. 78) , doubt , if you can , by whom Sextus Roscius was murdered. dubitābam tū hās ipsās litterās essēsne acceptūrus (Att. 15.9) , I doubt whether you will receive this very letter. [Epistolary Imperfect (§ 479 ).] quālis sit futūrus, nē vōs quidem dubitātis (B. C. 2.32) , and what it (the outcome) will be, you yourselves do not doubt. nōn dubitō quid sentiant (Fam. 15.9) , I do not doubt what they think. dubium illī nōn erat quid futūrum esset ( id . 8.8.1), it was not doubtful to him what was going to happen. Nōn dubitō in the sense of I do not hesitate commonly takes the Infinitive, but sometimes quīn with the Subjunctive:— nec dubitāre illum appellāre sapientem (Lael. 1) , and not to hesitate to call him a sage. dubitandum nōn exīstimā vit quīn proflcīscerētur (B. G. 2.2) , he did not think he ought to hesitate to set out. quid dubitās ūtī temporis opportūnitāte (B. C. 2.34) , why do you hesitate to take advantage of the favorable moment? [A question implying a negative.]