Definition
Used to indicate acceptance of an offer or agreement to something.
一言为定
"I'll offer you $50 for your old bike." "Done!"
「我出50美元买你的旧自行车。」「成交！」
"Can we meet at the coffee shop at 3 PM today?" "Done!"
「我们今天下午3点在咖啡店见面好吗？」「成交！」
"I'll proofread this report for you, but you have to buy me lunch." "Done!"
「我会帮你校对这份报告，但你要请我吃午餐。」「成交！」