--> What is Ren'Py?

Ren'Py is a visual novel engine that helps you use words, images, and sounds to tell stories with the computer. These can be both visual novels and life simulation games

--> Is Ren'Py easy to use?

Yes, for most part Ren'Py is very easy to use. But it does get complicated as you dive deeper into Ren'Py because for implementing those complicated system, you will need intermediate knowledge of Python and PyGame.
But as a casual developer, you would never ned to go that far, and even if you do, the lemmasoft community and (hopefully) we will be here to help you.