1.
ready consent; immediate agreement
Agreeing immediately without hesitation, as if answering 'yes, yes' (saying はい twice). Used to describe enthusiastic or unhesitating acceptance of a request or proposal.
Usage
Most commonly appears in the pattern 二つ返事で (with ready consent). The expression comes from the idea of answering 'はい、はい' (yes, yes) — responding so quickly that you say yes twice. Always implies a positive, willing response.
Despite 二つ meaning 'two,' this expression is positive. In everyday speech, saying はい twice (はいはい) can sound dismissive, but 二つ返事 as an idiom means enthusiastic agreement.