Dear [Name],
I am writing to express my heartfelt gratitude for your kind assistance. Your support has been invaluable, and I truly appreciate the time and effort you have invested in helping me. Your generosity has made a significant difference, and I am deeply thankful for your kindness. Thank you once again for everything.
Sincerely,
[Your Name]
This short letter aims to convey sincere appreciation while maintaining simplicity and elegance.
