Answer: Her face and a mirror.
Explanation:
In the passage, the speaker makes direct reference to (her) face being like a mirror, reflecting how he felt and showing his own expressions and thoughts.
In the lines from Shakespeare's "The Tragedy of Macbeth," Lady Macbeth is talking to herself while she is sleep walking. She feels so guilty that she cannot sleep properly. In that respect, she means that she and Macbeth do not need to fear anything because they are so powerful that nobody will believe they are responsible for killing Duncan. However, she does not actually think so - she is only trying to convince herself of it because she is under the impression that everybody is suspicious of Macbeth.
