Tending to or characterized by solemn and emphatic assertion; making strong claims or declarations.
From asseverare + -ory suffix (from Latin -orius, meaning 'tending to do'). This is an alternative adjectival form emphasizing the function of asserting seriously.
The -ory ending gives this word an even more formal, legalistic feel than asseverative—it's the kind of word you'd find in old legal documents where declarations had to sound as serious as possible.
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