Read the stanza from Shakespeare’s “Sonnet 18.” Shall I compare thee to a summer's day?
Thou art more lovely and more temperate:
Rough winds do shake the darling buds of May,
And summer's lease hath all too short a date:

What is the purpose of these lines?

to complain about the intense heat and humidity of summer
to persuade a loved one to visit during a warm season
to express love by likening a loved one to a nice day
to argue that hot weather is more pleasant than cold weather

To express love by likening a loved one to a nice day

Explanation:

I believe this should be the answer, though not entirely sure :O

malvolio only loves olivia because he thinks if they get married to olivia he will have a noble title, people to serve him, and fine clothes to wear. also he thinks if they get married he will have many expensive things, and he thinks he will be able to order toby around. malvolio only wants to be noble and boss people around he dose not really love olivia. but viola love for duke orsino is real she really loves orsino.

i think he will fail because he tried to get her to love him and she said oh, you are sick of self-love, malvolio. there is no slander in an allowed fool. so i think she knows what malvolio is trying to do. she knows that he only wants to marry her because he wants to be noble and boss people around so that it why i think she said oh, you are sick of self-love, malvolio. there is no slander in an allowed fool because she new he was selfish.

c. "but thy eternal summer shall not fade" (line 9)