Have to and Must (~야 되다, ~야 하다, ~야) | Live Class Abridged
The grammar form ~야 is more than just ~야 되다 and ~야 하다. It's also found in ~야지, and even just ~야 used by itself (and I'm not talking about yelling out "야!" to people).
Here are all of the uses of ~야, with detailed explanations and examples for each one. Check out the short abridged version of the full 2-hour live stream here~