Early Indian people were divided into castes, sort of like classes. The highest were in the Brahmin caste, who were the teachers, priests and scholars. Next were those in the Kshatriya caste (where Sita is), the warriors, kings, etc. The Vaishya caste came next, they were the merchants and the farmers. The Pariah caste was made up of the laborers. The last group of people were not considered to be in a class, they were simply the untouchables, mostly beggars, outcasts. There is a lot more to this system, but is not going to be discussed here.
As for the mythological Sita and her place in the Hindu culture...
You may have heard of the Indian epic the Ramayana, about a prince named Rama on a journey to save his wife Sita who was kidnapped by a Dark lord. Sita is supposedly a representation of a model wife, friend, lover, woman, etc. She is also believed to be an avatar (reincarnation in Hindu context) of the goddess Lakshmi, just as her husband being an avatar of the god Vishnu.
Claire's almost sure she's made a mistake in one of the details somewhere, so if anyone finds anything wrong in this part, feel free to correct her.