Confused by some lines of a movie
I watched a movie called “Georgy Girl” and I'm really confused by some lines of it.
The scene is that a man is playing a joke on a woman.
The man:"You're a two-timing broad."
The woman:"No, not broad."
The man:"Yes. Very long. But you are broad, too. Hey!Are you longer than you are broader, or is your broad broader than your long? How is your broader anyway, and your sister?"（while he is flirting with the woman.）
I don't undertand what does the "broad" mean. And I can‘t understand the "long" and the "sister" too.