Answer:
Shakespeare's famous quote, "The course of true love never did run smooth," means that love can be difficult, and you need to fight to keep it alive. Falling in love may seem easy, but there will be many obstacles that will test your resolve and dedication to your partner, which happens in any relationship.
When applied to Romeo and Juliet's story, this quote quite obviously fits their narrative. Romeo and Juliet fall in love; however, their families hate each other and won't let the two be together. Over the course of the play, many things happen that attempt to keep them apart, like the feud between the Montagues and the Capulets, Mercutio's and Tybalt's deaths, and finally, the death of Romeo and later on Juliet.
While they were alive, it was difficult to be together - the quote exemplifies that perfectly. They never had it easy - the 'star-crossed lovers' were doomed to fail from the very beginning.
