प्रसादे सर्वदुःखानां हानिरस्योपजायते।प्रसन्नचेतसो ह्याशु बुद्धिः पर्यवतिष्ठते॥
prasāde sarva-duḥkhānāṃ hānir asyopajāyateprasanna-cetaso hyāśu buddhiḥ paryavatiṣṭhate
Word by word
The verse says
In that clearness all his sorrows fall away. For someone whose mind has become clear like that, the understanding settles very quickly.
In plain words
The result, and it happens fast.
All sorrows fall away. Not some. And then the understanding settles āśu — quickly, without a long campaign.
After fifty verses of effort, Krishna says the last part is not effortful.
Where you've felt this · in health
You sleep properly for three nights after months of not. Nothing about your life has changed. The problems that looked unsolvable on Tuesday are just tasks now, and you did not solve any of them.
Going deeper
There is a shift of register here that is easy to read past.
Most of this chapter has described work: analyse, settle, restrain, act without craving. This verse describes something that happens to a person once the conditions are right. The sorrows fall away; the understanding establishes itself quickly.
Prasanna-cetasaḥ — one whose mind has become clear. The root is the same as prasāda in the verse before. Something has cleared, the way water clears when you stop stirring it — not by being worked on, but by being left alone long enough.
That image is worth holding, because it explains the relationship between effort and result in the Gita. The effort is all in not stirring. The clearing is not something you do.
Sarva-duḥkhānāṃ hāniḥ — the destruction of all sorrows. It is a large claim, and the Gita makes it without hedging. Whether you find it credible is a fair question, but the text does not soften it, and this edition will not either.