Curley’s wife’ loneliness is demonstrated by her dialogue.
Curley’s wife does not have a name, which demonstrates her isolation and lower status. She is lonely, and spends a lot of time “looking” for Curley, because this is socially acceptable behavior. She can interact with others if she is just looking for her husband.
The farmhands feel threatened by her presence. In fact, almost everyone on the farm is. There seem to be no other females, and no one for her to befriend. The men are standoffish or cautious when she is around, and accuse her of being a tart when she isn’t.
Curley’s wife’s reaction to Lennie and Candy demonstrates her loneliness.
"Well, I ain't giving you no trouble. Think I don't like to talk to somebody ever' once in a while? Think I like to stick in that house alla time?" (4)
Her words are both placating and accusatory. She wants to diffuse the tension, but she also does not want to be there. The ranch hands are her last resort in a search for companionship, and she resents them for that.
Curley's wife is aware that the men consider her trouble. She is annoyed by that fact. She fears that she will spend the rest of her life alone, ignored by them and her husband.