In plain words
What were those two faults? Keeping the water gourd hidden away was possessiveness; taking it and throwing it away in anger because Ubhayabhāratī had criticised him was Ahaṅkāra. “One who has not given up possessiveness and Ahaṅkāra cannot be one who has renounced all ties,” said Ubhayabhāratī. Then that sannyāsī went and fell at her feet and asked her to forgive his faults. “My son! Now you have truly renounced all ties,” said Ubhayabhāratī.
In the Mahābhārata, Karṇa had no Ahaṅkāra or attachment of any kind. You must become like Karṇa, not like Duryodhana and Duśśāsana. Every student must be a Karṇa; must listen to good things; must put them into practice; must experience Ānanda; must share with all the Ānanda they have experienced. This is your foremost duty.