Perhaps it is surprising to note that Lennie and Curley's wife have quite a bit in common in Of Mice and Men.
Curley's wife describes Lennie every time she sees him, suggesting his strength at their first meeting, suggesting his low social status next and finally addressing Lennie's humanity and his mental abilities.
Each of these depictions of Lennie parallel the changes in presentation which Curley's wife takes on over the course of the book. She is seen first as a manipulative and dangerous "tart", then as a friendless and bitter person, low on the social ladder of the ranch, and finally as a pathetic dreamer who suffers from a lifetime of disappointments.
In the barn, these two characters are finally see each other as "harmless" people, without malice or evil intentions. The reader can infer that these two figures both share the bottom rung on the social ladder of the ranch and we see that each of them is willing to act illicitly simply in order to hang onto a dream.
Curley's wife dreams of having friendships and being popular and so risks getting into trouble (and being harmed by Lennie) by staying in the barn alone with him. Lennie takes the same risk then goes further, harming her so that she won't ruin his chances at tending rabbits in the future.