An appraiser is like a grown-up who checks how much something is worth. Just like how your parents might look at something you made and say it's worth a high five, an appraiser looks at things like houses or cars or jewelry and decides how much money they are worth.
The appraiser has special tools and knowledge to figure out the value of things. They might look at things like how big the house is, how old it is, and what condition it's in. They also look at things like how much other similar houses have sold for, to help figure out how much money the house is worth.
This information is important for people who want to buy or sell things. If someone is trying to sell their house, they need to know how much it is worth so they can ask a fair price. If someone wants to buy a house, they don't want to pay too much money for it, so they get an appraiser to make sure the price is right.
Overall, an appraiser is like a super smart grown-up who knows how much things are worth and helps people make good decisions about buying and selling stuff.