In a confident and forceful manner; with bold claims or strong statements made directly.
From 'assertive' (adjective, from 'assert' plus '-ive') plus '-ly' (adverbial suffix), creating an adverb form of the common adjective 'assertive.'
While 'asserting' and 'asserting-ly' are theoretical options, 'assertively' is the actual word people use—it gained traction in psychology and communication studies where it describes a communication style (assertiveness training is now standard), giving the word real-world importance.
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