Orders with the status of "Pending" in WooCommerce are orders that have not actually been placed with Sezzle. You will not see any corresponding orders within your Sezzle dashboard, and you will not be receiving funds for those orders.
Orders typically appear in this status when a shopper either decides to not continue with the order (abandons the cart) or is declined for Sezzle. If they are declined, they are always given the option to return to your checkout to use another payment method.
We strongly advise against fulfilling these orders, as these are not orders that we will be collecting funds for. For most WooCommerce merchants, once the status changes to "Paid," it is an order that should be fulfilled.
If you are ever unsure, we strongly recommend checking your "Orders" tab within Sezzle, as that will list all orders that were processed by Sezzle.