"Celui qui a été soldat porte en lui un souvenir impitoyablement imprimé en lui et cela ne le quittera jamais"

Simplified Meaning:

Someone who has been a soldier experiences things that are so powerful and intense that they will remember them forever. These memories are deeply rooted in their mind and cannot be forgotten, no matter how much time passes. For example, imagine a person who went through a really difficult and scary time during a war, like seeing friends get hurt or being in great danger themselves. These kinds of memories leave a strong mark that changes the way they think and feel. Even after the war is over, these memories will always be with them. They might find it hard to sleep at night or feel anxious when they hear loud noises, because these events were so impactful. To deal with this, a person might need to talk to others who understand what they've been through or get help from a professional. It shows how some experiences change you forever and how important it is to support those who have been through tough situations.