A way to get a good fit when installing decorative molding is to install the first piece with a square end. Then cut the second piece at a 45-degree angle in a miter box or saw to expose the profile. Use a coping saw and follow the edge of the profile, under-cutting it about 3 degrees. This lets you get a good fit, even if the corner is not perfectly square.
Sump pits are intended to collect water from foundation perimeter drains. If there is a pump installed in the pit and no water is collecting in the pit, be sure to check the pump to be sure it is working. The easiest way to test your pump is to fill the sump pit to the point it will activate the pump, if the pump does not work replace it.