SB 10.46.29

tayor itthaṁ bhagavati
 kṛṣṇe nanda-yaśodayoḥ
vīkṣyānurāgaṁ paramaṁ
 nandam āhoddhavo mudā
Synonyms: 
tayoḥ — of the two of them; ittham — like this; bhagavati — for the Supreme Personality of Godhead; kṛṣṇe — Lord Kṛṣṇa; nanda-yaśodayoḥ — of Nanda and Yaśodā; vīkṣya — clearly seeing; anurāgam — the loving attraction; paramam — supreme; nandam — to Nanda; āha — spoke; uddhavaḥ — Uddhava; mudā — with joy.
Translation: 
Uddhava then joyfully addressed Nanda Mahārāja, having clearly seen the supreme loving attraction he and Yaśodā felt for Kṛṣṇa, the Supreme Personality of Godhead.
Purport: 

If Uddhava had seen Nanda and Yaśodā actually suffering, he would not have reacted with joy. But in fact all emotions on the spiritual platform are transcendental bliss. The so-called anguish of the pure devotees is another form of loving ecstasy. This was clearly seen by Uddhava, and thus he spoke as follows.