In English grammar, affirmative sentence is a traditional term for any statement that is positive, not negative. Also known as an assertive sentence or affirmative proposition.
In contrast, a negative sentence (which commonly includes the negative particle not or the contracted negative n't) contradicts—or negates—all or part of the meaning of a sentence. An example of a negative sentence is Rabbits don't fly. A sentence that lacks a positive meaning is sometimes called non-assertive or non-affirmative.