[Your letterhead, if desired; if not, your return address]
[Date of letter-month, day, and year]
[Recipient's first and last names]
[Street or P.O. box address]
[City, State ZIP code]
Dear [recipient's name]:
Happy Valentine's Day! Thank you for taking such good care of me every day, acting silly and laughing with me, for playing games with me, taking me to the playground, reading books to me, and cheering me up when I feel sad. I am so glad I'm your special little girl.
You are the best Mommy ever, and I love you SO much!!
Love and kisses,
[Sender's first and last names]