At the end of Chapter 2, after Mrs. and Mr. Morel become increasingly estranged due to Mr. Morel's drunkenness and violence, the narrator describes Mrs. Morel's changing feelings towards her husband using metaphor and paradox, two forms of figurative language:
As Mrs. Morel saw him slink quickly through the inner doorway, holding his bundle, she laughed to herself: but her heart was bitter, because she had loved him.
Note how the narrator describes Walter as "slinking" rather than "moving." This conveys to the reader that Mrs. Morel interprets his movements as snake-like, a subtle comparison that underscores the sense of foreboding and danger Mrs. Morel feels in her husband's presence. In literature, snakes typically symbolize evil; the serpent who tempts Adam and Eve to eat forbidden fruit in the Bible, for example, is a common reference. Lawrence presents this metaphor to the reader to suggest Walter is cunning and not to be trusted.
The next figure of speech, the phrase "her heart was bitter," is meant to be interpreted figuratively, not literally. Bitterness is typically associated with things that are unpleasant. In this instance the word "bitter" expresses the unhappiness, anger, and resentment Mrs. Morel feels towards her husband's heavy drinking. The narrator then explains to the reader that Mrs. Morel's feelings of bitterness are because she used to love him; she feels both affection and hostility towards her husband, two emotions that at first glance appear to oppose one another. This is an example of a paradox, a figure of speech that appears to contradict itself. Lawrence presents this paradox to the reader to reveal a deeper truth about the complexities of love. All in all, Lawrence implies Mr. and Mrs. Morel's relationship is bittersweet in nature, captured succinctly in the image of Mrs. Morel's embittered, transformed heart.