The Collaborative International Dictionary of English v.0.48:

Reassertion \Re`as*ser"tion\ (r[=e]`[a^]s*s[~e]r"sh[u^]n), n.
   A second or renewed assertion of the same thing.
   [1913 Webster] re-assess

WordNet (r) 3.0 (2006):

reassertion
    n 1: renewed affirmation [syn: reassertion, reaffirmation]