We assure you that such things will not happen again in our future deliveries.
We'd like to avail ourselves of this opportunity to assure you of our prompt and careful attention in handling your future orders.
Our products are always as good as the samples we send, I can promise there will be no debasement of quality.
I guarantee that there is no difference in quality between the products we'll send you next month and what's samples you saw just now.
I can promise you that the products we send you will be of A-1 quality.
Our products are surely of standard quality.
I give you my word that the payment will be made not later that the end of June.
I promise I will check into these problems, and find out if they were our fault.
We can make sure that these goods will avoid being damaged during the transit.
We will provide a fresh guarantee for the protection of the equipment repaired.