Thank you very much for…
I am writing this letter to thank you for …
I am writing to express my sincere thanks for …
I feel greatly indebted to you for …
I really do not know how to express my gratitude for your help.
I would like to convey in this letter my heartfelt thanks to you for…
I am writing to tell you how greatly I appreciate all you have done for me…
I don’t know how to thank you for your kindness to me.
I warmly appreciate for your hospitality.
We are indebted to you for your help.
With deepest gratitude I write you’re here few lines.
I do appreciate it.
I appreciate more than I can say.
I must thank you again for your generous help.
My true gratitude is beyond the word’s desciption.
I feel most obliged to thank you once more.
I am most grateful for your selfless donation.
Please accept my gratitude as always.
Best wishes for your health and every happiness.
My thanks to you for your kindness and assistance when I …--and my love for you, always!
I am writing to thank you, on behalf of …, for the lovely time we had at your party last night.
I feel deeply indebted to you and I really do not know how to thank you enough for your help.
If it had not been for your assistance in giving me first aid, I fear that the consequence might have been much more serious.
It is generally held that it was your quick-witted response in that emergency that has led to this satisfactory outcome.
Thank you very much for your kind hospitality and the honor you showed me during my visit…
It was nice of you to..
Please have no hesitation in writing to me should you want me to do something for you…
It was kind and thoughtful of you to…