The confirmation messages are stored as part of the form object, not part of the entry. If you have more than one confirmation, you will need to pull both the form and the entry, and determine from the entry data which confirmation would have been shown, then show that. If the confirmation has any dynamic information from the entry, you will need to add that back in as well.
I’m thinking, maybe this is the solution of my problem :
Is there a way to save the confirmation message in the entry ?
Maybe in a field in pre submit post ?