Question

Why doesn't Romeo want Juliet to be associated with the moon?

Answer 1

In Romeo and Juliet, the moon is seen as a symbol for a change: its phases change all the time throughout  the month, so if someone compares love to the moon, this means that their love can change, too.

So the correct answer is: because the moon symbolizes the shifting tides and he wants Juliet to love him consistently

Answer 2

Romeo doesn't want Juliet to be associated with the moon because the moon is less beautiful than the sun.

In fact, Romeo compares Juliet to the sun because she is out of his reach, very bright and beautiful, and is like the sun that guides him.