(Scene from Yuddha Kanda of the Ramayana, where Trijata is seen thrice with Sita. On the top right, Trijata (in a red saree) is seen twice in the Pushpaka Vimana, surveying the battlefield and seeing Rama and Lakshmana bound by Indrajit s weapon. In the right side (bottom panel), she is seen with Sita in the Asokavana - Wiki)

A demoness devoted to God and warden of Sita during her imprisonment in Lanka. (Glossary for the Vahinis)

Ravana kept three ladies to guard Sita during her incarceration in the Asokavana. One was Sarama, the wife of Vibhishana, younger brother of Ravana. The other two ladies were Ajata and Trijata who were none other than daughters of Sarama; they were very considerate towards Sita, keeping up her sagging morale all the while by their comforting words. Sita wondered whether such good people also existed in Lanka. In fact, it was due to their consoling words and protection that Sita could hear her ordeal courageously. Though Sita was imprisoned in Lanka, Ravana did not dare to touch her. He knew that he would be reduced to ashes if he touched her without her consent. He was all the while pleading with her to accept him. When Ravana stooped to the level of denigrating Rama and threatened her, she even without even looking at his face, plucked out a blade of grass and threw it before him saying, ‘You are a mean fellow. You are not worth even this blade of grass. How dare you denigrate Rama in front of me, you vile and vicious wretch!’ (SSS Vol. 41, p. 115)

Trijata’s Dream

Trijata was a pious devotee, who had both worldly wisdom and spiritual experience. (RKRV Part II, p. 131)

One night Trijata, daughter of Sarama had a foreboding dream. The dream vividly showed Lanka as being totally dry and arid. It showed all the trees as having withered and fallen. The royal palace was seen reduced to ruins and Ravana was staggering about without even water to drink. She understood that what she foresaw to be Ravana’s fate was a direct consequence of his own wicked deeds. At the same time, she was helpless and could do nothing but feeling sad. (SSB 2002, p.116)

Among the ladies belonging to the demonic community appointed to guard Sita in the Asokavana, there were two by name Ajata and Trijata. They were the daughters of Vibhishana, the younger brother of Ravana. One day while consoling Sita, who was weeping, Trijata told her ‘Mother! Last night, I had a dream. I saw one monkey entering Lanka and setting the city ablaze. I also saw very clearly that Rama invaded Lanka, killed Ravana and took you to Ayodhya.’ Ajata too counselled Sita saying, ‘Oh! Mother! It is true. I too had a similar dream. You need not be sorry anymore.’ (SSS Vol.39 p.240)

Vibhishana was crowned the emperor of Lanka. Throughout the length and breadth of the land, the name of Rama was resounding. Then Rama sent for Sita. Sisters of the Rakshasa clan! Take note, I never get dreams. I haven’t seen any so far. So if I dream at all, know it will certainly come true. It will happen just as in the dream. Moreover, the realisation, in actual fact, of the dream will not take long. Things must happen just as I dreamt, within four or five days.’ (RKRV Part II, pp. 131-132)

Both of them gave a lot of love and kindled faith in Sita. In fact, their father Vibhishana was a devotee of Rama. Hence, his daughters too developed devotion towards Rama.  (SSS Vol.39 p.240)

Sarama and her daughter are shown the ring brought by Hanuman:

(Hanuman meets Sita in the Ashoka vatika, where she is surrounded by rakshasis like Trijata.- Wiki)

Sarama, the wife of Vibhishana and her daughter, Trijata, came to the tree and fell at the feet of Sita sitting disconsolate thereunder. They enquired about her health. Since they were partial towards her, Sita spoke to them about how the dream of Trijata had come true, and how a monkey had actually entered Lanka in accordance with it. Sarama and Trijata showed extreme enthusiasm and excitement when they heard the account of what had happened. They plied Sita with questions, in their eagerness to know all details. Sita showed them the monkey perched on the branch and the Ring it had brought. They both pressed the ring on their eyes in reverent adoration. (RKRV Part II, p. 137)

Hanuman found that these three ladies were the only friends of Sita in Lanka. It was due to the solace and assurance provided by them that Sita survived.  (SSB 1996, p.58)