Inform through email that not accepting management trainee offer

Dear Michelle,

I hope this email finds you well. I am writing to inform you that I will not be accepting the offer of the position of Management Trainee, from ABC. I really appreciate the care and friendliness extended to me during this time. Foremost, I am grateful that ABC granted me an extension so that I could fully consider my options. At this time, I feel that ABC is not the best fit for me. It was an extremely difficult decision for me to make, as evident in my request for a month long extension. I again want to thank you and everyone else at ABC for this great opportunity and for your help and support through this time period.

Sincerely,
Irwin Jones