A dicent is not an assertion, but is a sign capable of being asserted. But an assertion is a dicent. According to my present view (I may see more light in future) the act of assertion is not a pure act of signification. It is an exhibition of the fact that one subjects oneself to the penalties visited on a liar if the proposition asserted is not true.
http://www.commens.org/dictionary/entry/quote-letters-lady-welby-46