Canto 2 -
Ayodhyā-kāṇḍa
Chapter 12: Kaikeyī Reaffirms her Demands
Text 2.12.88

शुद्धभावो हि भावं मे न तु ज्ञास्यति राघवः।
स वनं प्रव्रजेत्युक्तो बाढमित्येव वक्ष्यति॥

śuddha-bhāvo hi bhāvaṁ me na tu jñāsyati rāghavaḥ
sa vanaṁ pravrajet yukto bāḍham ity eva vakṣyati

śuddha-bhāvaḥ hi = of a pure mind; bhāvam = [true] intention; me = my; na tu = not; jñāsyati = will know; rāghavaḥ = Rāghava; saḥ = He; vanam = to the forest; pravrajet = will go; yuktaḥ = when engaged [in this manner]; bāḍham iti = “alright”; eva = just; vakṣyati = He will say.

Rāghava of a pure mind will not know my [true] intention.  When engaged [in this manner], He will go to the forest. He will just say, “Alright.”

Rāma would consider Daśaratha to be pure and not be aware of Daśaratha’s intention behind his request. Therefore, He will agree [to go to the forest].