Business Letter for promotion

Dear Mr ……,
I just want to express my gratitude to you for the unexpected promotion , I’m grateful and honored to accept this promotion .
Really I appreciate all of the opportunities and support that you have given ,also your unique perspective , positive altitude , guidance and encouragement.
I am looking forward to my new responsibility , I assure that I would definitely an asset for the corporation and ultimately be a partner to achieve our corporation goals , I’ll certainly devote my full efforts in the future to meet your expectation .
Thank you so much.
Respectfully yours,