SB 10.46.29

tayor itthaṁ bhagavati
 kṛṣṇe nanda-yaśodayoḥ
vīkṣyānurāgaṁ paramaṁ
 nandam āhoddhavo mudā
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.
Uddhava then joyfully addressed Nanda Mahārāja, having clearly seen the supreme loving attraction he and Yaśodā felt for Kṛṣṇa, the Supreme Personality of Godhead.

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.