It would degrade me to marry Heathcliff now; so he shall never know how I love him: and that, not because he's handsome, Nelly, but because he's more myself than I am. Whatever our souls are made of, his and mine are the same; and Linton's is as different as a moonbeam from lightning, or frost from fire. (9.92)

You may have seen the "I am Heathcliff" shirts around town—these are the famous lines they're parodying. Yep, Cathy and Heathcliff are not just made for each other…they're one and the same. Too bad she just got done telling Nelly, her maid, that he ain't never gonna put a ring on it.

OMG: it would "degrade" her to marry the man she really loves? The man she says is—wait for it—her very self? Talk about drama-rama. We can almost imagine Cathy's exaggerated eyebrow raise after Nelly asks her about Heathcliff.

This bit of dialogue employs a couple of similes to compare Catherine's less-than-robust future husband, Linton, to herself (and by extension, Heathcliff). Notice how lightning's brightness is something that would block out moonbeams? And just what do you think fire does to frost? Linton's not going to know what hit him.