If you are feeling misgivings about accepting a job offer, set your anguish aside and write a letter of notification to decline it. You may feel a bit embarrassed about the situation now, but contrast it to the very real possibility of quitting the job in a week or two, when the situation would become even more precarious. Remember that you never know when your path may intersect again with this prospective employer, so don’t burn bridges in your letter. You can handle this situation with grace and professionalism -- and relieve yourself of the burden of accepting a job that clearly isn’t right for you or your career.
Begin your letter by thanking your contact person for her time and her extension of the job offer. This may be one of the few times in business writing that you choose graciousness over a straightforward explanation of why you are writing, but it will set an important tone.
Explain that after “giving this new career opportunity a great deal of thought,” you have decided that it is not “the right fit” for you after all. State very clearly that you have decided that it is in your best interests, as well as the company’s, to decline the job offer.
Take on the role of a confident diplomat by noting the positive attributes of the company, perhaps in terms of its reputation or the “interesting challenges” it faces in the marketplace. Be positive and sincere, remembering what attracted to you to the company or position before your misgivings set in.
Express your confidence that you could have made great contributions to the company’s mission but believe that you should not begin a new job with “anything less than a deep conviction that it will be a mutually beneficial and long-term collaboration.” Apologize succinctly for "any inconvenience" your decision might cost the company.
Thank your contact person for her time and "the benefit" of learning more about the company. Wish her good luck in her “future endeavors.” Express your wish to see her at business events, conferences or other meetings, if relevant. Doing so will leave an important impression that your decision is not personal; it’s strictly business.
Read your letter carefully, checking your spelling, punctuation and grammar. Read it aloud – then send it with the quiet confidence that you are making the right decision.
Do not reveal your career plans or the terms of another job offer, if you have one. Keep your letter focused squarely on the company and why it is you are politely declining its job offer.