The woman said to him, "I know that Messiah comes," (he who is called Christ). "When he has come, he will declare to us all things."
Will tell us all things - Jesus had decided the question proposed to him John 4:20 in favor of the Jews. The woman does not seem to have been satisfied with this answer, and said that the Messiah would tell them all about this question. Probably she was expecting that he would soon appear.