Emphasize - Accentuated: As she took her stance for a short mashie shot, Dexter looked at her closely. She wore a blue gingham dress, rimmed at throat and shoulders with a white edging that accentuated her tan.
In this passage it is saying that the white edging of the dress made the darkness of her skin stand out. Emphasize means the same as stand out of accentuate.
Childish sulkiness or bad-temper - petulance: During dinner she slipped into a moody depression which gave Dexter a feeling of uneasiness. Whatever petulance she uttered in her throaty voice worried him.
She is described as being in a moody depression. This best fits with the definition of sulkiness or bad-temper.
Practical, Ordinary - mundane: "You're not. I like you. But I've just had a terrible afternoon. There was a man I cared about, and this afternoon he told me out of a clear sky that he was poor as a church-mouse. He'd never even hinted it before. Does this sound horribly mundane?"
Another word for mundane is ordinary. Mundane is used to give ordinary a more boring connotation.
~Hope this answers your question!~
