Answer:
First and foremost, Juliet shows little to no feelings towards Paris, she seem completely uninterested in him. Whereas with Romeo, they both immediately fall in love.
Secondly, Romeo is a Montague, therefore he can't be with Juliet because of their family's feud. Paris, however is not a Montague, and thus can wed Juliet.
Thirdly, Juliet is being betrothed to Paris, but with Romeo, She'd wed him because she was in love with him.
Lastly, They both love Juliet (In one way or another, with Romeo being more faithful and loving)
