There are several ways to close a letter of encouragement. All closing sentences should aim to motivate the reader, helping the reader feel more upbeat. Some basic examples include writing either "Sincerely" or "Keep it up," as the letter's closing.
While letters of encouragement differ in their content, the main goal is to leave the reader feeling more positive and even happier. Letters of encouragement often include words of affirmation. The end of the letter is especially important for concluding well while offering readers memorable words of encouragement to take with them into the days ahead, making the closing sentence especially powerful.
One idea to conclude a letter of encouragement is to quote a famous person. For example, if the letter of encouragement is for a fearful person and the letter aims to avail the person's fears, a good conclusion to the letter might be Franklin D. Roosevelt's famed statement, "We have nothing to fear but fear itself."
Letters of encouragement can also help someone who is going through a tough time. These letters often close by reminding the reader that they are not alone. One such example is: "I am proud of you and your success. Know that I am here for you if you ever need me for anything."