Why doesn't Romeo want Juliet to be associated with the moon? because he wants Juliet's love to be "in the light" because the moon symbolizes the shifting tides and he wants Juliet to love him consistently because the moon is Diana, the goddess of chastity because the moon is less beautiful than the sun
The answer is "he wants Juliet to love him consistently"
Romeo doesn't want Juliet to be associated with the moon because he wants to love him consistently. Moon isn't always there so might be her love. Instead, Romeo compares Juliet to the sun. Juliet is out of reach, bright, and beautiful like the sun. She guides him like the sun too.