। ॥ ९९ ॥
In plain words
You drop the mind's busyness with objects, and it settles on śravaṇa and nothing else. That is the other śānti, the mind's own — and its one mark is sattva still mixed.
Close to the Sanskrit
Having abandoned engagement with sense-objects, the mind's abiding on hearing alone — and this is the other peace of the mind, having mixed sattva as its sole mark.