In Act I, Scene 1, after the street brawl between the Montagues and the Capulets, Benvolio and Lord Montague talk about Romeo and how sad and depressed he has been lately. Benvolio says he will attempt to find out what is bothering Romeo. During his discussion with Romeo it is revealed that Romeo is in love with a woman who does not share his love. Benvolio suggests Romeo should forget her and "Examine other beauties." In the next scene they come across Capulet's servingman in the street. The man, being illiterate, is unable to read the party list Capulet gives him and is seeking out someone to read it for him. He bumps into Romeo, who reads the list out loud, discovering the name of Rosaline, the girl he loves. When Benvolio hears this he vows (though this word is never used) to show Romeo other girls that are more beautiful than Rosaline at the party. Benvolio says,

At this same ancient feast of Capulet’s
Sups the fair Rosaline whom thou so loves,
With all the admirèd beauties of Verona.
Go thither, and with unattainted eye
Compare her face with some that I shall show,
And I will make thee think thy swan a crow.

In Act I, Benvolio vows he can show Romeo that Rosalind can be forgotten, or to die trying.