In the following passage, which words are emphasized? How and why are the words emphasized?
Father, and wife, and gentlemen, adieu.
I will to Venice; Sunday comes apace;
We will have rings and things, and fine array;
And kiss me, Kate; we will be married a Sunday.
There is also the emphasis required by the rhythm of iambic pentameter (stressed syllables emphasized in bold):
Fath-er, and wife, and gentle-men, a-dieu
I will to Ve-nice; Sun-day comes a-pace.
We will have rings, and things, and fine a-rray
And kiss me, Kate, we will be married o'Sun-day.
Except for the first line, which has a feminine ending (on an unstressed syllable), all lines have their necessary stressed and unstressed syllables -- five each.
Understanding the iambic rhythm really points out, for example, the stress on the word "will" as mentioned in other responses to this question. You also notice that Shakespeare almost always stresses the action or verb ("will", "married", etc). in a line and never the pronoun ("I," "We," "me").
To me, the word that is most emphasized in this passage is the word "will." It is emphasized by being used so many times.
In my opinion, this word is emphasized because emphasizing it helps to bring out what is going on in the play at this point. At this point, Petruchio has announced his intention to marry Katherina and to "tame" her. In this passage, he emphasizes his intent to dominate her.
He uses the word "will" so many times to show that what he says is what is going to happen. He leaves no doubt about who is in charge. He is not saying "we might" or "I'd like." He is saying these things will happen. This is a very bold and aggressive way of speaking and it shows that he feels that he is in charge.
In the play "The Taming of the Shrew" Kate is to be wed to a man whom she detests but is curious about. Her father has promised her to him. Kate is a very demanding and stubborn woman and the gentleman takes the bet that he can wed her and tame her.
The story is a battle of will between the two. He has bragged to everyone that he will be wed so he is emphasizing that on Sunday he will be off to Venice. Sunday is emphasized twice as that is the day of his commitment and when he will have won part of the bet.