You may want to setup a shipping fee calculator to give a sense of shipping cost in the cart page. Check the demo
Else you need to get it fully customized for the specfic scenario and commit the rate at cart page
Actually I don't need a calculator because the shipment will take place at a fixed cost.
I wish it was very simple.
Item 1 10€
Item 2 15€
Shipping cost 5€
my client wants it that way...
This can be done through code customization and effort will depend on how robust that solution needs to be for example how it should work with shipping profile settings or you just need a quick workaround which needs to be maintained etc.