De or het leaseverklaring?

The correct Dutch article is:

de leaseverklaring

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

How to use leaseverklaring

the leaseverklaringde leaseverklaring
this leaseverklaringdeze leaseverklaring
that leaseverklaringdie leaseverklaring
our leaseverklaringonze leaseverklaring
your leaseverklaringjouw leaseverklaring
every leaseverklaringelke leaseverklaring
which leaseverklaring?welke leaseverklaring?
a big leaseverklaring / the big leaseverklaringeen grote leaseverklaring, de grote leaseverklaring