Dear Sir, 

You will already have received formal acknowledgment of your order of 12th July, but as this is your first order with us, I feel I must write to tell you how pleased we were to receive it and to thank you for the opportunity you have given us to supply the goods you need.

I hope our handling of this order will lead to further business between us and to a happy and lasting association. We shall certainly do our best to make it so.

Yours faithfully,