buy into something

Từ điển Oxford Advanced Learner 8th

ˌbuy ˈinto sth derived
1. to buy shares in a company, especially in order to gain some control over it
2. (informal)to believe sth, especially an idea that many other people believe in
•She had never bought into the idea that to be attractive you have to be thin.
related noun ↑buy-in
Main entry: ↑buy_derived