Lennie was obsessed with soft objects. Curley's wife allowed Lennie to touch her hair and couldn't stop. Lennie was so strong he broke her neck.
Lennie accidentally killed Curley's wife while trying to stop her from screaming during a struggle. Lennie, who has a tendency to be rough without realizing his own strength, unintentionally caused her death in a moment of panic.
Chapter 5 page 91-92
Lennie kills Curley's wife by shaking her so hard that her neck breaks -- remember, he is a big strong man. He does not kill her on purpose. He is only shaking her like that because he wants...
Curley attacks Lennie out of anger and aggression, blaming him for the death of his wife. In retaliation, Lennie crushes Curley's hand, revealing his immense strength and inadvertently causing Curley significant harm.
Lennie didn't intentionally want to kill Curley's wife he did it on an accident. Lennie was in the stable and he had just killed his pup so he was hidding it and she walked in and started talking to him. They talked for a while about Curley and then she said something about her hair being really soft and she put Lennie's hand on her head to feel it. George then started rubbing her head and when she asked him to let go he didn't and she started to yell but Lennie shook her and tried to tell her to be quiet but in the end he accidentally broke her neck by shaking her (which killed her).
Curley's wife has killed his dream through her stupidity. In his mind, she was the reason for her own death and the reason why Curley wants to kill Lennie. George will not participate in the dream without Lennie, and therefore Candy will not go to the farm at all. He will remain at the ranch and live the rest of his pessimistic life.
Curley's wife is implying that Lennie got the bruises on his face from fighting with Curley. She recognizes that Curley is quick to pick fights with the workers on the ranch.
Curley's Wife
curley's wife tells Lennie that "You are nuts , but you kinda nice fella".
all of the ranch hands see Curley's Wife in the barn, lennie is the first to see her, then candy, then george and then the rest of the ranch hands
Curley's wife unintentionally provokes Lennie by letting him stroke her hair too roughly, leading him to accidentally kill her in a moment of panic.
Lennie choked Curley's wife