Use the word "dear" when talking to or about someone who is close to you.
My dear wife is making dinner in the kitchen.
She is my dear, dear friend.
He was the dearest of friends.
There is nothing more dear to me than this.
This organization is near and dear to my heart.
We use "dear" when addressing a person, formally or informally.
Dear Mr. Smith: I am writing this letter in response to your concerns. (This would be a typical greeting in a letter.)
Dear Grandma, How are you doing? I hope you are well. (This would be typical of a letter sent to a family member.)
Yes, dear. I will help you with the housework this weekend.
Thank-you for being such a dear! (To use "dear" as a noun is a manner of speaking more typical of women than men. Coming from a man, this would sound effeminate.)
Dear Mom and Dad….
The word "dearly" is an adverb used for formal, solemn occasions such as weddings and funerals:
Dearly beloved, we are gathered here today to participate in the marriage of two people who…
Our dearly departed mother was the person who held our family together.
Note: The word "dear" is a term of endearment, a word used to show affection or care for another person. In some cases, it’s similar to "honey," "sweetie," or "baby."
Dear Mom and Dad….