What is darn tootin?

"Darn tootin'" is a colloquial expression that originated in the United States in the 20th century. It is used as a way to express agreement or affirmation, similar to phrases like "you bet" or "absolutely". The word "darn" is a milder form of the word "damn", and "tootin'" is derived from the word "toot", meaning noise or sound. The phrase likely originated from the idea of a sound being so definitive that it cannot be denied, thus affirming something with certainty. It is commonly associated with Western movies and cowboy culture.