It's a deal.
deal: 交易
It's a deal. 表示成交。
在口语中表示:就这么决定了,就这么约定了, 就这么定了!
在口语中可以简化成:Deal!
1. 就这么定了,我们这周五去旅游吧。
It's a deal! Let's go traveling this Friday.
2. 今天你来我家吃饭,就这么说定了。
You will come and eat at my place. It's a deal!
3. A:下周一起吃个饭吧。
B:好啊,就这么定了。
A: Let's have dinner together next week.
B: Good. It's a deal!