I am not sure I fully understand your question, but if you mean "can I be sure that my income from job is correct registered?".
If it is a normal job where you receive your montly pay note, with calculations of salary, tax, AM-bidrag etc, then it will be income that the authorities will know about - it will be automatically reported to the "income register" (danish: indkomstregistret).
And when you apply for dagpenge from your A-kasse, the A-kasse will withdraw the information about your income from "indkomstregistret".
If you have income in form of B income - then you must be aware that this will not appear in the income register.
So if you have B-income you must remember to tell your A-kasse this, when you apply for dagpenge.
B income can also be used to fulfill the income requirement.