Please note that you will need to repost your other questions, as only one is to be asked and answered at a time.
It is Mr. Jaggers who utters the words of the title. For, he approaches Joe one evening at the Three Jolly Bargemen and suggests that they discuss an important matter at Joe's house. In the parlor, then, Jaggers states that he is there as a "confidential agent of another." He goes on to say,"And the communication I have got to make is that he [Pip] has Great Expectations"; Pip will come into
a handsome property...and be immediately removed from his present sphere of life and from this pace and be brought up as a gentleman--in a word, as a young fellow of great expectations.
However, there are conditions attached. He must bear the name of Pip and the name of the benefactor is to remain a secret until this person chooses to reveal it firsthand to Pip, and he must never make inquiries as to who this person is. Of course, Pip thinks, "Miss Havisham was going to make my fortune on a grand scale."