[T]he Buddha unequivocally uses the word Truth in place of Nibbāa: ‘I will teach you the Truth and the Path leading to the Truth.’3 Here Truth definitely means Nirvāṇa.

Now, what is Absolute Truth? According to Buddhism, the Absolute Truth is that there is nothing absolute in the world, that everything is relative, conditioned and impermanent, and that there is no unchanging, everlasting, absolute substance like Self, Soul or Atman within or without. This is the Absolute Truth. Truth is never negative, though there is a popular expression as negative truth. The realization of this Truth, i.e., to see things as they are (yathābhūtaṃ) without illusion or ignorance (avijjā), is the extinction of craving ‘thirst’ (Taṇhakkhaya), and the cessation (Nirodha) of dukkha, which is Nirvāṇa. It is interesting and useful to remember here the Mahāyāna view of Nirvāṇa as not being different from Saṃsāra. The same thing is Saṃsāra or Nirvāṇa according to the way you look at it—subjectively or objectively.