A51/B75: ". . . The receptivity of our mind, its power of receiving representations in so far as it is in any wise affected, is to be entitled sensibility . . . ."
Sensibility represents objects through intuition. "Our nature is so constituted that our intuition can never be other than sensible; that is, it contains only the mode in which we are affected by objects" (A51/B75). That is, unlike the understanding's ability to produce its objects (concepts), sensibility is not originating of its representations (intuitions).