This sound is from Avatar: The Last Airbender Soundboard

Avatar The Last Airbender (abbreviated as ATLA), also known as Avatar The Legend of Aang in some regions or simply Avatar, is an American anime-influenced animated television series.
See also: Avatar: The Last Airbender (comics), Avatar: The Last Airbender (franchise), List of Avatar: The Last Airbender episodes, List of Avatar: The Last Airbender characters, Katara (Avatar: The Last Airbender), and Avatar: The Last Airbender (season 2).