noun
ready reply; quick answer
Common mistake for 二つ返事 (ふたつへんじ), which is the correct expression for an immediate, willing reply. This form is often used erroneously, but the intended meaning is the same.
See also: 二つ返事
「一つ返事で引き受ける」は誤用で、正しくは「二つ返事で引き受ける」です。
Using 一つ返事 for 'accepting immediately' is a mistake; the correct phrase is 二つ返事.