noun
pleasant feeling; comfortable feeling
Refers to a sense of satisfaction, ease, or well-being. Often used in contexts like 快心の笑み (a satisfied smile) or 快心の作 (a work one is proud of).
彼は快心の笑みを浮かべた。
He gave a satisfied smile.
この絵は彼の快心の作だ。
This painting is a work he is proud of.