becomes completely happy.

As soon as irrevocable loving service is established in the heart, the effects of nature's modes of passion and ignorance, such as lust, desire and hankering, disappear from the heart. Then the devotee is established in goodness, and he becomes completely happy.

Srimad Bhagavatam - Canto 1 Chapter 2 Verse १९
चित्र :अशोक लव