美滋滋 (měi zī zī): 아주 행복하다.

After receiving her birthday gift, my little sister smiled with great joy, so happy that she couldn't even be bothered to eat.

As soon as he got his driver's license, he happily drove us around in his new car, feeling very pleased.

Hearing the teacher praise him, Xiaoming felt very happy inside and studied even harder.

She happily put on the newly bought dress and twirled in front of the mirror several times.