01Born of the furrow
Janaka tells the story himself in Bala Kanda. He was ploughing the ground for a yajna when a girl rose out of the furrow, and he raised her as his daughter and named her Sita, the furrow. She was promised to whoever could string Shiva’s bow; kings came, failed, and laid siege to Mithila in their anger. Rama lifted the bow and it broke in the middle with a sound like thunder. At the wedding Janaka placed her hand in Rama’s and said, this is Sita, my daughter, your companion in dharma.
02She would not stay behind
When Rama told her to stay in Ayodhya and serve his parents, Sita refused. A wife shares her husband’s fortune, she said, and the forest with him would be her palace. When he still hesitated she stung him: did my father give me to a woman dressed as a man? Rama gave way. In the forest, Valmiki keeps her voice sharp. She sent Lakshmana after the cry of the golden deer with words so harsh that he left her. The Lakshmana Rekha, the line he draws before going, is not in Valmiki; it comes from later tellings.
03In the Ashoka grove
Ravana kept her in a grove of ashoka trees, ringed by rakshasis, and gave her two months to yield. She sat under a shimshapa tree in the one yellow garment she had been taken in. When Ravana spoke to her she placed a blade of grass between them and answered the grass, not him. Hanuman found her there. She would not ride away on his back: she would touch no man but Rama of her own will, and Rama must win her back himself. She gave Hanuman her chudamani and told him of the crow at Chitrakoot, a thing only Rama knew.
04Through fire, into the Earth
After the war Rama spoke to her before the whole army with a coldness that shocked even the vanaras. Sita had Lakshmana build a pyre and walked into it, and Agni himself rose and placed her in Rama’s arms. In the Uttara Kanda, talk among the people of Ayodhya makes Rama send her away, and she gives birth to Lava and Kusha in Valmiki’s ashrama. At the Ashvamedha she makes her last vow: if she has thought of no one but Rama, let Madhavi, the Earth, take her. The ground opens, a throne rises, and the Earth carries her down.
Janaki Navami, on the ninth of Vaishakha Shukla, is kept as her birthday.
Famous verses
शक्या लोभयितुं नाहमैश्वर्येण धनेन वा। अनन्या राघवेणाहं भास्करेण प्रभा यथा॥
Sita to Ravana: I cannot be tempted by power or wealth. I am not apart from Raghava, as light is not apart from the sun.Valmiki Ramayana, Sundara Kanda 21.15