प्रतिष्ठितेति सत्य इति तस्मादपि दी-क्षितमाहुः सत्यं वदेति सत्ये ह्येवदीक्षा प्रतिष्ठितेति कस्मिन्नु सत्यं प्रति-ष्ठितमिति हृदय इति होवाच हृदयेनहि सत्यं जानाति हृदये ह्येव सत्यं प्रति-ष्ठितं भवतीत्येवमेवैतद्याज्ञवल्क्य ॥ २३ ॥
In plain words
On truth, comes the answer. Which is why people tell someone newly initiated: speak the truth — because initiation itself stands on nothing but that. And what holds truth up? The heart, he says — because it's the heart that knows what's true. That's where truth finally comes to rest. Just so, Yajnavalkya, just so.
Close to the Sanskrit
'[Initiation is] founded' — 'on truth', he said. Therefore they also say to an initiated person: 'speak the truth' — for it is on truth indeed that initiation is founded. 'On what, then, is truth founded?' — 'On the heart', he said; 'for it is by the heart that one knows truth; it is in the heart indeed that truth comes to be founded.' 'Just so it is, Yājñavalkya.'