Asseverate

to declare earnestly or solemnly; affirm positively; aver.
historical examples

and i hereby do fully and freely declare and -sseverate, that the woods did not tremble to a kiss, and that the lovers did.
life of lord byron, vol. 6 (of 6) thomas moore

she did not -sseverate any more, nor even say she was innocent.
sue, a little heroine l. t. meade

they lacked a definite opinion to entertain and a cry to -sseverate.
in the name of the bodleian and other essays augustine birrell

no one appeared to think it worth while to -sseverate the fact, for it was self-evident.
black ivory r.m. ballantyne

they -sseverate with vehemence that in all the seven-and-thirty plays there is no such thing as a native woodnote wild.
a century of science and other essays john fiske

he could -sseverate with some justice, “i have never written an insincere note.”
musical portraits paul rosenfeld

it has more solemnity than declare, and more composure and dignity than -sseverate, which is to -ssert excitedly.
english synonyms and antonyms james champlin fernald

“wh-why, n-budy ever heard me talkin’ things that’s tol’ in secret,” mike made haste to -sseverate.
the lookout man b. m. bower

as to whether she was young, middle-aged or only well-preserved, no one was in a position to -sseverate.
anderson crow, detective george barr mccutcheon

and she was very glad also that he did not deign to -sseverate that he had been ignorant of his half-sister’s plight.
hilda lessways arnold bennett

verb
(transitive) to -ssert or declare emphatically or solemnly
v.

1791, from latin -sseveratus, past participle of -sseverare “to affirm, insist on, maintain,” from ad- “to” (see ad-) + severus “serious, severe” (see severe). related: -sseverated; -sseverating.