It is important / It is expected
This expression is used to express a general truth or expectation about behavior or actions.
Examples
人は約束を守るものだ。
People are expected to keep promises.
子供は挨拶をするものだ。
Children should greet others.
親に相談するものだ。
It is important to consult your parents.
Quick check
人は約束を守る___。