Caitanya-caritāmṛta 19.211
śānta-rase — ‘svarūpa-buddhye kṛṣṇaika-niṣṭhatā’ “śamo man-niṣṭhatā buddheḥ” iti śrī-mukha-gāthā
[shaanta-rase — ‘svaroopa-buddhye krishnaika-nishthataa’ “shamo man-nishthataa buddheh” iti shree-mukha-gaathaa]
Blended reading (Sanskrit + English inline)
śānta-rase — ‘svarūpa-buddhye kṛṣṇaika-niṣṭhatā’ “śamo man-niṣṭhatā buddheḥ” iti śrī-mukha-gāthā
“When one is fully attached to Kṛṣṇa’s lotus feet, one attains the śamatā stage. The word ‘śamatā’ is derived from the word ‘śama’; therefore śānta-rasa, the position of neutrality, means being fully attached to the lotus feet of Kṛṣṇa. This is the verdict from the mouth of the Supreme Personality of Godhead Himself. This state is called self-realization.
Purport
The corresponding verse from the Bhakti-rasāmṛta-sindhu (3.1.47) follows.
— A.C. Bhaktivedanta Swami Prabhupāda
My note
Source: vedabase.io