Assertion/əˈsɜːrʃn/ Definition 1 of 3Pro Tip 1/3Emphasis on Belief Used to express strong belief in what you're saying, even if not proven. His assertion that aliens exist was met with skepticism. Pro Tip 2/3Conveys Confidence Shows you're confident in your statement, setting aside potential doubts. She made an assertion of her innocence with great confidence. Pro Tip 3/3Potential Challenge May be used to present a point that others can challenge or debate. His assertion that the policy would fail invited heated debate.