"But woo her, gentle Paris, get her heart,
My will to her consent is but a part;
An she agree, within her scope of choice
Lies my consent and fair according voice."
In other words, Paris needs to win Juliet's heart -- having her father's permission to marry her is only part of the battle. Capulet wants his daughter to desire the match as well; he will not agree to a match that she does not want.
