• there is no doubt about that
• apparent, doubtless, downright, evident, indisputable, indubitable, patent, undeniable, undoubted, unequivocal, unquestionable
• to aggravate, to drive to despair
• to challenge, to contest, to discredit, to dispute, to doubt, to impugn, to question
• to despair, to give way to despair
• agonized, despairing, desperate, forlorn, last-ditch, to be in despair
• despairingly, desperately, doubtfully, forlornly, like hell
• undisputed, unquestioned
• to be in despair, to despair
• to cast doubt on sg, to cast doubts on sg
• incontestable, incontrovertible, uncontroversial, uncontrovertible, undisputed, unquestionable