Final answer:
Benvolio wants Romeo to go to the feast at Capulet's Mansion to help him move on from Rosaline and find a new love interest.
Step-by-step explanation:
In Act 1.4 of Romeo and Juliet, Benvolio wants Romeo to go to the feast at Capulet's Mansion because he hopes it will help Romeo forget about Rosaline and find someone new to love. Benvolio believes that by attending the feast, Romeo can compare the other young ladies to Rosaline and realize that there are other beautiful women in the world.
Learn more about Romeo and Juliet Act 1.4