Source : Webster's Revised Unabridged Dictionary (1913)

Asseverate \As*sev"er*ate\, v. t. [imp. & p. p. {Asseverated};
   p. pr. & vb. n. {Asseverating}.] [L. asseveratus, p. p. of
   asseverare to assert seriously or earnestly; ad + severus.
   See {Severe}.]
   To affirm or aver positively, or with solemnity.

   Syn: To affirm; aver; protest; declare. See {Affirm}.

Source : WordNet®

asseverate
     v : state categorically [syn: {assert}, {maintain}]