This verse (chaupai) is from the Balakanda chapter of Shri Ramcharitmanas.
सुनु सिय सत्य असीस हमारी। पूजिहि मन कामना तुम्हारी॥ नारद बचन सदा सुचि साचा। सो बरु मिलिहि जाहिं मनु राचा॥
This verse (chaupai) is from the Balakanda, in the context of Sitaji's worship of Gauriji. Gauriji has blessed Sitaji.
Meaning : O Sita, listen to our true blessing, your desire will be fulfilled. Narada's word is always pure (free from doubt, delusion, etc.) and true. Whatever your heart is attached to, that blessing you will receive.