In Romeo and Juliet, what does the Nurse think about love and marriage in Act I?
It is Act I scene 3 that you need to examine carefully to find the answer to this question. You might want to think how this scene would be staged. It appears that the Nurse has a comic function as she constantly gives her commentary on what Lady Capulet is trying to say when she has a serious talk with Juliet about the husband her parents have selected for her. Though well-intentioned, it is clear that her interruptions could be viewed as annoying or humorous. Many productions have Lady Capulet either ignoring the Nurse or getting increasingly annoyed with her comments, and some have Juliet moving to protect her.
However, it is clear that the Nurse believes that marriage is a good thing and should be aspired to. No mention of course is made of love. Marriage for the Nurse is obviously about marrying for advancement. Note how the Nurse says that her one wish is to see Juliet married. When Juliet says marriage is "an honour that I dream not of," the Nurse agrees with her, saying she has obviously "sucked wisdom from thy teat." When Lady Capulet announces who the man is, the Nurse's agreement only focuses on the physical appearance of Paris:
A man, young lady! Such a man
As all the world.--Why, he's a man of wax.
The Nurse clearly focuses on the outward appearance. To her, Paris is wealthy, of good social standing and handsome. What more could her Juliet want? Note her comment to Lady Capulet's words that Juliet would make herself "no less" by marrying Paris:
No less? Nay, bigger! Women grow by men.
This is a very revealing remark. From the Nurse's point of view, marriage was the only way for a woman to "grow" and to become more important. Love does not enter into the equation. This is why we can see later on in the play that the Nurse urges Juliet to forget about Romeo and marry Paris. Marriage is an alliance designed to improve your position and nothing more.