Hello, To answer your question precisely, I will need more details; such as what company, what role/position, what duties, and so on. However, the least you need to have is usually B2. I worked in China for 4 years and that was definitely the minimum requirement at the majority of workplaces.

Hello, 'Disinterested person' may be someone who has a neutral attitude, or can make decisions without being affected by the surrounding opinion. 'Uninterested person' may be someone who lacks enthusiasm and curiosity. Quite often you may find such people at conferences and meetings (^__^)