After having been addressed by the Brahmarishi Valmiki about innocence of Devi Sita, Shri Ram joined his hands in reverence and then looked at his wife with teared eyes.

"Aapke shabd paryapt pramaan hai. Kintu Brahmarishi, maine kabhi Sita par sandeh kiya hi nahi tha. Sita ne pehle bhi apni pavitrata ka pramaan diya hai, kintu fir bhi praja asantusht thi, iss liye maine Sita ka tyaag kiya tha. Iske liye mai kshama praarthi hu. Mai jaanta hu aur iss baat ko maanya bhi karta hu ki woh do balak mere hi putra hai. Ab mai punah Sita par apna prem nyochavar karna chaahta hu." Shri Ram said.

He then looked at Devi Sita, dressed in ochre, looking like a tapasvini, Shri Ram was overcome by delight at even a mere glance at her but he restrained it.

"Sitey, mere man mei tumhare prati na hi koi sandeh tha, na hai aur na hi kabhi hoga. Kintu ek baar praja ke liye, apne pavitrata ka pramaan dedo. Jisse yadi abhi bhi kisi ke man mei shanka ho, uska nivaran ho jaaye." Shri Ram requested.

When the foremost among the gods realized what Shri Ram intended, they all assembled, placing Brahma at their head. There were the Adityas, the Vasus, the Rudras, the Vishvedevas, the hosts of the Maruts, the Ashvins, the seers, the gandharvas, the troupes of the apsarases, and the saadhyas.

Indeed, all the gods and all the foremost seers were there. At that moment, Vayu, auspicious, pleasant, delightful, and bearing a heavenly fragrance, refreshed the entire mass of people.

Luv Kush looked at the king who in reality was their father, they both then looked at Rameshwari, who was in truth, their elder sister. The Ram-suta looked at the Ram-Sut, and gave them a nod of assurance, with a sad smile.

Everything now seemed to be falling into the place, Devi Sita just had to prove her innocence once more and all will be fine, at least that's what they thought.

Devi Sita saw all those who were assembled here, she joined her hands in reverence and cast down her eyes, and lowered her face.

"Yadi Ram ko chhod maine kis anya purush ke baare mei vichaar bhi nahi kiya hai toh Mata Dharini, mujhe apni goud mei sthaan de." Devi Sita said. Hearing it, the eyes of Shri Ram widened.

Everyone got shocked seeing that from the surface of the earth there arose an unsurpassed, heavenly throne. It was borne on the heads of great serpents of immeasurable might. It was adorned with every jewel, and it was celestial with its celestial beauty.

Then Bhudevi, the goddess of the earth, who was on that throne, took Devi Sita in her arms.

"Padharo putri." Bhudevi said and made devi Sita sit upon her throne.

At the sight of Sītā entering Rasātala while seated on that throne, a continuous celestial shower of blossoms rained down upon her. Suddenly there arose a great cry of "Excellent!" among the gods.

"Utkrisht ! O Sita tum utrisht ho jisne aisa pavitra acharan dikhaya !" They said.

When Vaidehī had entered the underworld known as Rasatal, all the people and the sages there cried out, 'Excellent ! Excellent !' in Shri Ram's presence.

Rameshwari stood there holding her hand over her mouth, her Sitey Maa, just descended unto earth and left them all ? Tears that were brimming in her eyes, now fell freely.

"Mata !" Luv Kush cried, regaining themselves from the shock.

Rameshwari looked at them, and rushed to the side of her brothers, holding them in her embrace before they fall on their knees.

"Mata ! Mata !" The twin brothers cried, as she too sobbed silently holding them close.

Shri Ram leaned on the his wooden staff, his eyes clouded with tears, hanging his head, his mind distressed, the Sita-pati was profoundly heartbroken. He kept weeping and weeping.

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A/N

So there is no clear answer as to why Devi Sita took this step, not even Valmiki Ramayan answers this.

But in my humble understanding, I feel like she knew that doubts will again be raised if she stays.

Like Shri Ram became Maharaj and the people raised questions. Now after Ashwamedh, he will become Samrat, imagine how many more will question her ?

It's also a matter self-respect, ki for how long will she have to keep proving her innocence ?

So maybe she took this step, to prove her chastity once and for all. Because I don't think there was another way, to stop the accusations and malicious rumours, permanently.

Because if there had been, Shri Ram would've taken it right away. But sadly there wasn't.

JAI SIYA RAM 🥲🙏