Answer and Explanation:
Juliet would still love Romeo, regardless of his last name and the family he belongs to. We can see this, because Juliet herself claims that the name Romeo is meaningless to her, because with any name he would still be the Romeo she fell in love with. Juliet claims this soon after learning that Romeo is a Montague, when she was already in love. The role of "forbidden love" in Juliet's attraction to Romeo is small, as Juliet falls in love with Romeo before learning that their family were enemies and would never allow them to be together. You may know this from the speech Juliet makes on her bedroom balcony when she declares her love for Romeo.
It is important to remember that "Romeo and Juliet" is a play written by Shakespeare. In this story, we get to know the tragic romance lived by Romeo and Juliet and learn how petty intrigues can have horrible results.