Rest in Peace in Japanese...

安息 means to rest, to go to sleep, to rest peacefully, or in repose, in Chinese characters, Japanese Kanji, and old Korean Hanja.

安穩 can mean a steady, stable, sedate, and calm mind.

Other translations include “body and mind at rest,” or “peace and comfort.”

安心 can be defined as relief, peace of mind, feeling at ease, to be relieved, to set one's mind at rest, and easiness.

安心 is a nice word that encompasses great meanings within just two characters. Some of the other meanings include pacifying, settling the mind, and peace of mind. It's also the idea of feeling a sense of security, safety, and confidence in your state of well-being.

This can be used by everyone, but some consider it to be a Buddhist concept (You'll find it in your Zen dictionary).

Note: Can be romanized as Anshin or Anjin in Japanese.

My Australian friends always say, “No worries, mate.” It's caught on with me, though I drop the “mate” part since it confuses my fellow Americans.

If you would like to express the idea of “no worries,” 放心 is the best and most natural way to say it in Chinese.

The characters you see to the left can be translated as “put your mind at rest” or “to be at ease.” You could literally translate “no worries,” but it doesn't “flow” like this simple Chinese version.

For your info, the first character means to release, to free, to let go, to relax, or to rest. The second character means your heart or your mind.

Note that in Japanese and Korean, this holds the similar meaning of “peace of mind” but can also mean absentmindedness or carelessness, depending on context.