Peace of Mind in Japanese...

和平 is the Chinese order for these two characters, which means peace but can also be translated as amicability, specifically, or mildness. 和平 is often translated as a simple way to say “peace of mind.” This combination is used in Korean Hanja to mean “peace and harmony.”

Alone, the first character means peace and harmony.
The second character means balance when read by itself.

Note: 和平 are often seen in the opposite order in Japanese with the same meaning (You'll sometimes find them in this order in Japan, so either way is OK).

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.

內心平靜 is a Chinese and Japanese phrase that is a direct translation of the western idea of inner peace.

The first two characters contain the idea of “heart,” “innermost being,” or “deep in the/your inner mind.”

The last two characters mean “tranquil” and “serene.”

I have seen this phrase used as “inner peace” for art prints and even on the side of coffee cups. But I think the translation is too literal. It feels like a direct translation from English rather than a nicely composed Chinese or Japanese phrase. See my other entries for “inner peace.”

See Also:  Serenity | Simplicity | Peace

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

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

忍耐は心の平和をもたらす means “patience brings peace of mind,” in Japanese.

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

These Japanese Kanji, 安心立命, can be translated as “religious enlightenment” or “spiritual peace gained through faith.”

Other dictionaries define as “spiritual peace and enlightenment” or “keeping an unperturbed mind through faith.”

My Buddhist dictionary defines it as “spiritual peace and realization of enlightenment.”

In the Zen school, this is about settling one's body and life; attaining complete peace, and establishing one's course of life in accord with the ultimate reality.

眉を開く is a Japanese proverb and expression that means “to feel relieved,” “to forget about one's troubles,” or “to settle into peace of mind.”

The literal words suggest relaxing your eyebrows or face. Allow worry or concern to go away, and just be content with “letting it be.”

Note: Because this selection contains some special Japanese Hiragana characters, it should be written by a Japanese calligrapher.

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.

失意泰然 is a very old Japanese proverb that suggests “keeping calm and collected at times of disappointment,” or “maintaining a serene state of mind when faced with adversity.”

It's hard to relate individual character meanings to the overall meaning unless you also understand Japanese grammar. The word order is very different than English. That being said, here's the character meaning breakdown:
失 To miss, lose or fail.
意 Feelings, thoughts, meaning.
泰 Safe, peaceful.
然 Like that, in that way, however, although.

Using these definitions in English, we might say, “Although you may fail or lose, have a feeling of peace and calm.”

無事 is a Zen Buddhist term meaning no problem and no trouble.

無事 is the Zen state of perfect freedom from troubles and leaving secular affairs behind.

Sometimes this is used to describe the state of satori and complete tranquility of mind.

Written as 無事に with an extra Hiragana at the end, this becomes an adverb to describe something in the condition of safety, peace, quietness, and without troubles.

無事 (Buji) can also be a given name in Japan.

This has more meaning in the Japanese Zen Buddhist community than in China or Korea, where it can mean “be free” or “nothing to do or worry about.”