De or het mandatering?

The correct Dutch article is:

de mandatering

Rule Words ending in -ing: almost always de. See the rule

How to use mandatering

the mandateringde mandatering
this mandateringdeze mandatering
that mandateringdie mandatering
our mandateringonze mandatering
your mandateringjouw mandatering
every mandateringelke mandatering
which mandatering?welke mandatering?
a big mandatering / the big mandateringeen grote mandatering, de grote mandatering