One good quote dealing with appearance rather than reality is a line spoken by Friar Laurence to Juliet when he councils her to fake her death in Act 4, Scene 1. Friar Laurence tells Juliet that after drinking his potion, she "shall, stiff and stark and cold, appear like death." In other words, she will appear to be dead, but in reality we know that she is not really dead yet.
Another good quote that can be used to prove the theme of appearance vs. reality is spoken by Juliet to her mother after Juliet learns that Romeo has killed Tybalt. In Act 3, Scene 5, Juliet declares to her mother, "Indeed, I never shall be satisfied with Romeo, till I behold him--dead." We know this statement is a lie. Juliet has already forgiven Romeo and does not wish to revenge Tybalt. The reality in this line is that she truly wishes to behold Romeo, but not dead.
There are several instances in which the word "true" is used, which can also serve to demonstrate the theme of appearance vs. reality. Again, in Act 4, Scene 1 in which Juliet begs Friar Laurence for advise her on how to get out of her betrothal to Paris, Juliet declares that her "true heart" will turn to suicide, saying that she will slay herself with a "bloody knife" if Friar Laurence cannot think of a way to preserve her "true honour." The use of the word "true" alludes to reality because that which is true, is also real.