Translation of "musti" into English

Ini musti jadi serius Aku berjanji pada pacarku Aku melewati semua ini

This must be so serious I promised my girlfriend I was through with all this

Kita musti memastikan agar anak di seluruh dunia mendapat pendidikan.

And we have to make sure that children are educated around the world.

Ya, kita peduli pada planet ini dan musti membuat keputusan tepat.

Yes, we care about the planet. Yes, we need to make the right choices.