Final answer:
Juliet expresses her fear that the love and decisions she’s making with Romeo are too hasty, comparing their fleeting nature to lightning, which disappears quickly.
Step-by-step explanation:
Juliet's fears are evident in the quote “I have no joy of this contract tonight. It is too rash, too unadvised, too sudden; too like the lightning, which doth cease to be ere one can say it lightens. Sweet, goodnight.” Her concerns are that their love and the decisions surrounding it are happening too quickly, likening them to the brief life of a lightning strike that ends before one can acknowledge its existence.
This comparison highlights her uneasiness that the intensity of their sudden love affair may burn out as quickly as it flared up. Her use of the words “rash,” “unadvised,” and “sudden” emphasize a fear of the repercussions that may come from such haste in their relationship.