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".
"Letters of intent are often touted as a 'non_legally binding' way to get the parties to set forth in writing what the undertaking is among them relative to a transaction. Too often, parties will sign such a document, feeling that they have little or nothing to lose by doing so... [True, that's] one of the attractive elements of the letter of intent [its purported non_binding nature]. However, courts have found letters of intent to create binding obligations, even if the letter itself does not explicitly state that it is binding... certain provisions within the document may indeed [still] have legal effect."