At the end you should sign off with "sincerely yours" or any other related salutation. If you are writing a letter of intent for graduate school then it would have a different content. First of all letter of intent would start with your name, address, contact number and email address. After you have mentioned the date, you should then add a salutation like "Dear Sir/Mam".
The Letter of Intent is not binding, and rather silly at the worst of times. An LOI by definition only registers intent to purchase, and it specifies this intent weakly, and due to its ambiguity should be avoided.