Chinese phrase
那就这么定了 nà jiù zhè me dìng le
Meaning
then it's settled
When to use it
It confirms that a decision is final and agreed. It often closes a simple discussion after people choose a plan.
Example dialogue
周末去海边还是爬山？ zhōu mò qù hǎi biān hái shì pá shān
Are we going to the beach or hiking in the mountains this weekend?
爬山吧，那就这么定了。 pá shān ba nà jiù zhè me dìng le
Let's go hiking. Then it's settled.