As usual, the meanings are broad and overlap. Nowadays, "belongings" is usually used in phrases like "before exiting the train, check to make sure you have all your belongings." It means all of the small items you are carrying with you. It emphasizes that you are carrying them on your person. It usually means physical items that can, for example, be counted. "Property" emphasizes ownership. "Property" means "mine, not yours." I can lend you my lawnmower, but it is still my property. "Property" can be something big and important. It is often used to mean real estate--land and buildings. It can be something abstract; a copyright on a song is "intellectual property." "Possession" emphasizes control. You: "I'm going to take the bus into town." Me: "Oh, it's raining, let me lend you my umbrella to take with you." 1) My umbrella is in your possession. It is no longer in my possession. 2) As you get off the bus, you forget to make sure you have all your belongings. My umbrella is one of them. You leave it behind on the bus. 3) My umbrella is no longer in my possession, but it is still my property, and I expect you to return it. What an awkward situation! 4) But perhaps, with luck, you will be able to find it at the bus station in the "lost property office."

“Material possessions” is a phrase that is often used to contrast with non-material qualities. “She doesn’t have much in the way of material possessions, but everyone is jealous of her genius.” “Belongings” tend to be small things that you have on you. The emphasis is less on ownership. “The students in the school have to place their belongings in their locker before going to gym class” (Legally the items might be owned by their adult parents) “Possessions” would include bigger things and focuses more on ownership. “Her valuable possessions are a diamond ring and a fairly new pick-up truck” “Property” can be used in different ways. Sometimes it would include all smaller possessions and land and building that is owned. Other times, “property” refers only to land and buildings, sometimes designated by the term “real property”. “The county property tax is paid annually on real property located in the county”. Money in a bank account is often referred to as an asset, though it could be considered either a possession or property in the right context.

David K has a very good answer.