Chloe is an anime-original character. She is a villager of Pasroe and has known Lawrence for a long time. In fact, Lawrence taught her how to be a merchant. Despite still not knowing how she should feel about him, she respects him as her teacher. (Source: Wikipedia)
She is an anime-original character, meaning she does not exist in the manga/light novel version of Spice and Wolf. In fact, she replaced a character that only appears in the novels and manga: an old male acquaintance of Lawrence named Yarei.