You stored the entire form contents into one cookie, not separate cookies, therefore, there is no cookie named naam. The cookie that stored the form information is called:
Therefore, you would have to store the naam form element in a separate cookie and display that cookie. To set that cookie, go to the server behavior panel and click on the '+' button and go to the WA Cookies Toolkit section and select the Set Cookie Value server behavior. Name the cookie what you would like it to be named and how long you want it stored for and in the Value field, click on the lightning bolt button next to the input box and select the naam input box from the form. Then you can use the display cookie using the name you chose for the cookie.