The nurse was gone for 3 hours when going to see Romeo about the marriage.
She has to wait three hours. She sent the nurse at 9, and the nurse returned around 12.
The Nurse has been gone for about three hours when she returns in Act 2, Scene 5 of "Romeo and Juliet."
Juliet is impatient because she sent the nurse to meet with Romeo and ask when they can see each other and the nurse hasn't returned despite how long she's been gone.
Juliet complains: "Now is the sun upon the highmost hill Of this day's journey, and from nine to twelve Is three long hours; yet she is not come."
The Nurse leaves to meet Romeo at 9 o'clock but only returns at noon as stated in this section of Juliet's speech: "Now is the sun upon the highmost hill Of this day's journey, from nine till twelve Is three long hours, and yet she is not come." Act 2 Scene 5 So 3 hours
The nurse angers Juliet by taking too long to deliver the message from Romeo and by speaking poorly of him, questioning his sincerity. Juliet is frustrated with the nurse's lack of urgency and loyalty to Romeo.
Three hours
3 hours
The answer is in Juliet's speech at the beginning of Act II Scene 5: "The clock struck nine when I did send the nurse . . . and from nine till twelve is three long hours, yet she is not come."
It is not clear that the marriage views of everyone today are the same. And it is not clear at all that Romeo and Juliet's marriage was typical of their time (whatever that was) either. Contrast Romeo and Juliet's views on marriage with those of Capulet, or even more so, of Paris. For Paris, marriage was a commercial transaction: he wanted "the chinks" and made a deal with Juliet's father. Or contrast Juliet's views with those of the Nurse. The Nurse had the "easy marriage, easy divorce" attitude: if Juliet's marriage with Romeo wasn't working out, it was time to move on. This is a not uncommon attitude these days. Romeo and Juliet pledged themselves to each other for their lives and beyond death. That was an unusual attitude then, and it still is, but it is not unheard of.
it takes her one day
After the marriage, but before the wedding night, at the beginning of Act 3 Scene 2, Juliet is full of anticipation of the sexual fulfilment of her marriage. "Come civil night, thou sober-suited matron, all in black and learn me how to lose a winning match, played for a pair of stainless maidenhoods." She is looking forward to losing her virginity (as Romeo will lose his) but "winning" by making their marriage complete. "O I have bought the mansion of a love, but not possessed it." She has the name of wife, but not yet the reality.