Hanuman Chalisa, Chaupai 22
"sab sukh lahai tumhārī sarnā" is Chaupai 22 of the Hanuman Chalisa, which Tulsidas wrote in Awadhi. It means: Whoever takes refuge in you finds every happiness. With you as protector, there is nothing to fear. Read it slowly, one half at a time, and say the Awadhi aloud.
सब सुख लहै तुम्हारी सरना ।तुम रच्छक काहू को डर ना ॥sab sukh lahai tumhārī sarnātum racchak kāhū ko ḍar nā
Whoever takes refuge in you finds every happiness. With you as protector, there is nothing to fear.
Tulsidas, Hanuman Chalisa, Chaupai 22, Gita Press reading
This line praises Hanuman or speaks to the reader. It does not retell one episode, so there is no single place in the Ramayana to point to.
Krishna's last word on refuge: give up every other support, take refuge in me alone, and do not grieve. Read Bhagavad Gita 18.66
Awadhi text: Goswami Tulsidas, Gita Press reading, checked against three Gita Press printings and Rambhadracharya's Mahaviri. English meaning and word glosses: Wisdom's own, following the traditional reading, edited by Ankur Shukla.