The Nyāya Sūtras is an ancient Indian Sanskrit text composed by Akṣapāda Gautama, also known as Aksapāda, and is the foundational text of the pracina or Old Nyaya school of Hindu philosophy.
The text contains 5 parts divided further into chapter and contains over 500 sutras.
Babaji is reading from Nyāya-darśanam with the Vātsyāyana's bhāsya, which includes the Hindi commentary by Dhundhiraj Shastri.
Love is the only thing that does not end up in frustration because it does not have any purpose behind it. Conditional love is not pure. When that condition is not satisfied then there is frustration. It is not possible to have frustration in love. If you are experiencing frustration in love that means there is something wrong and you should try to correct it.