Originally posted by @suzianneAgain, it's important to note the context of the verse - "love" is something greater than a mere emotion. See my reply to divegeester.
You can try to save people, and yes, sometimes you fail.
But sometimes, when people don't wanna be saved, you just gotta let them go. You cannot let them drag you down. But I thought the ending to Romeo and Juliet was total BS, too.
People may fail, but Love never does. If someone fails you, it sure wasn't Love's fault.