One can never take for granted that the receiver has the same reality as the sender. One can never take for granted that the receiver will interpret the message the way the sender intended. Communication is not absolutely finite. To some extent communication with language is vague and misleading. If Angela says a word, for example "trust", she has a certain meaning attached to it in her reality. She has had certain experiences with the subject matter, she has made certain conclusions and she has certain perceptual filters. The meaning of the word is everything associated within her reality.
What travels across the communication channel is NOT all the word associations Angela made, and NOT the intentions she had using it. What crosses the channel are symbols. When Bob hears the word or sentence he will interpret it based on his experiences, his perceptions and opinions. He might supplement the verbal information with non-verbal information such as body language. He might also assume what it is supposed to mean.