There are certain words and phrases that mean satisfied, happy, or otherwise contented
я рад
я доволен
я удовлетворен
In english, "I am happy", that is "being happy" is a state of mind and a state of being, an emotion, can be disconnected from a particular event or set of circumstances.
What word or phrase would closest replicate the meaning of the English word for the emotion of happiness and the phrase "I am happy" .