Curley's wife is often referred to negatively and as a tart throughout the novel but it's not as straight forward as that, as she is a very complex character. Here are some points I've found when I've been looking at the novel, in the PEE/PEEL (point evidence explanation language) form.
Point: Curley's wife is seen as a tramp and a 'floozy' by most of the other ranchmen.
Evidence: 'I think Curley's married... a tart!' (said by Candy)
Explanation: Candy has been on the ranch for many years so his views are representative of the other men on the ranch. It is a very biased opinion and it alienates her from George and Lennie before they've even met her, because it doesn't allow them to form their own judgement of her. It also means that the reader's first opinion of her is a negative one and makes her hard to like from the start.
Language:The ellipsis is important as it heightens the impact of the word 'tart', therefore emphasises Candy's disapproval of her.
Point: She is desperate for attention from the other men.
Evidence: 'heavily made up' 'her body was thrown forward'
Explanation: The fact that she has taken the time to make her eyes look 'heavily made up' shows that she is clearly making an effort to look attractive for the other men to get hold of…