Dear Mr. /Mrs.,
I am writing to you because I would like to take over this task. After reading your requirements and job description, I found myself a suitable match for this job. I consider that I am suitable for this task because I am an extremely well organized person, but also attentive to details. More than that I have done these tasks in other jobs.
I offer seriousness and punctuality and I can complete this task fast. In addition to all this I assure you that I am open to the requirements and details you need.
I'm glad to work for you.
Best regards, Andreea