Lokah Samastah Sukhino Bhavantu
may everyone, in the whole world, be happy.
This is an ancient saying very popular in India. It is widely known across the country. Though it is in Sanskrit, the words used are very simple and part of many regional Indian languages. Here is an explanation at yogapedia
My understanding and translation
Though I’m no linguist, the version which feels most proper is below:
Let all the world be at ease
The key difference is the use of “ease” instead of “happiness”. I think there are more valid words for happiness than sukha which is used in this shloka. Ananda is more suitable to indicate happiness and joy. Also to me, sukha denotes a comfortable, easy, pleasant state than being happy or joyful, etc.
Use as a prayer or in meditation
This shloka or prayer or mantra can be used for meditation and bringing ease into your experience. When all the world is at ease, naturally you also are at ease. You are not at odds with the world nor the world is at odds with you.
Chronic stress is a state where the mind and body feel under threat. Meditation and prayer are excellent ways to bring balance to the system and thinking, experiencing, and embodying the concept of Lokah Samastah Sukhino Bhavantu does help to bring equilibrium and to restore the natural flow of energies.