Even though he was (Yudhisthira) doubtful about it, he was obliged to inquire frankly from Arjuna on the basis of Sri Narada's indication

Expressions researched:
"So even though he was doubtful about it, he was obliged to inquire frankly from Arjuna on the basis of Śrī Nārada's indication"

Srimad-Bhagavatam

SB Canto 1

All the inquisitiveness of Mahārāja Yudhiṣṭhira about the world situation was already conjectured by Mahārāja Yudhiṣṭhira on the basis of Lord Kṛṣṇa's disappearance from the vision of the world, and this was now disclosed by him because of the acute dejection of Arjuna, which could not have been possible otherwise. So even though he was doubtful about it, he was obliged to inquire frankly from Arjuna on the basis of Śrī Nārada's indication.

SB 1.14.44, Translation and Purport

Or is it that you are feeling empty for all time because you might have lost your most intimate friend, Lord Kṛṣṇa? O my brother Arjuna, I can think of no other reason for your becoming so dejected.

All the inquisitiveness of Mahārāja Yudhiṣṭhira about the world situation was already conjectured by Mahārāja Yudhiṣṭhira on the basis of Lord Kṛṣṇa's disappearance from the vision of the world, and this was now disclosed by him because of the acute dejection of Arjuna, which could not have been possible otherwise. So even though he was doubtful about it, he was obliged to inquire frankly from Arjuna on the basis of Śrī Nārada's indication.