Lesson #438 - Fill In The Blank

For the record, at the time of posting this, a Google search for the phrase "I could tell you but then I'd have to love you" returns exactly zero hits. Which brings to question, why? Why has this phrase never even been used in a romantic comedy of middling quality? This really wouldn't work as a memorable line in said middling quality movie? Calling Sandra Bullock or Rachel McAdams!