April 15, 2012
Dear Mr./Ms. Bossname,
I know that we have had several discussions about this matter, but I am afraid that I must reiterate my resignation as (position) from this company, effective (date.) Thank you for accepting this notice and my final decision on the matter.
I have enjoyed my time here and I appreciate your offer, but I believe at this time that it would be best if I continue with my original trajectory. My last date is firm, but I will be glad to help train whomever you bring in as my replacement.
Thank you again for your understanding. I wish you and the company the best of luck in the future.