प्रसादे सर्वदुःखानां हानिरस्योपजायते। प्रसन्नचेतसो ह्याशु बुद्धिः पर्यवतिष्ठते ॥

prasāde sarva-duḥkhānāṁ hānir asyopajāyate prasanna-chetaso hyāśhu buddhiḥ paryavatiṣhṭhate

In that Peace the extinction of all pains ariseth for him, for of him whose heart is peaceful the Reason soon attaineth equilibrium.

In plain words: When a person finds that peace, all their suffering comes to an end. A peaceful heart soon leads to a calm and steady mind.