How to tell my seven-year-old daughter about him moving in this Sunday?

Seven years old is too young to grasp the mechanics of an arranged match, but old enough to notice a stranger’s shoes in the hallway and a new wardrobe in the guest room. Waiting until a few days before he moves in to explain things will make the house feel chaotic and unsafe to her, because children that age measure stability by routine. Sit her down today with her favorite snack and tell her plainly that a new person is coming to live with you permanently, and that your parents helped choose him because he is a kind man who also lost someone he loved. She is going to ask why she was not consulted, and the honest cost of this approach is that you will have to sit through her anger, confusion, or tears without getting defensive or pretending it is a game she gets to vote on. You can tell her directly that you know this is a big change she did not ask for, and that while you are bringing him into your home, her room and her place in your heart are not changing at all. Do not lean on the new cupboard to break the ice; address the person moving into it. Let her ask the same question five times and answer it gently each time. Show her that his arrival does not mean she has to love him immediately, but that she does have to treat him with basic politeness as an adult in the house. The next few weeks will involve some slamming doors and quiet resentment, and you will have to absorb that friction so she learns she can express her upset without the household falling apart.