You should know はず. It is easy and useful, therefore you have no excuse :)
Hazu shows an expectation that something should happen. In other words, you are pretty sure something is true. Let`s see how it works...
To add はず to any adjective just add it...
そのかばんは、高いはずです。
sono kaban wa, takai hazu desu.
That bag must be expensive.
[It is expected to be expensive]
Just add it to the simple form of any verb
あなたは、ゴジラを知っているはずです。
anata wa, gojira o shitteiru hazu desu.
You should/must know Godzilla.