The training is very brutal both physically and mentally. You will train in the heat and desert of North Africa. The food and water is minimal. They will do everything in their power to break you. By French law only foreigners can join the Legion. The training is so intense that few actually make it though the training. Being severely injured is very common (broken bones, concussions, exhaustion, stroke, etc.) They are not friendly and have no intention of being your friend. Unless you speak French you will not understand the language and orders that are given. That is no excuse, but you will learn. If you make it through the training you will be part of the Legion for, i think seven years. But, you don't become a French citizen unless you complete a second tour of duty. If you do complete the second tour of duty, you will be given citizenship and you can retire in Chateau in Provence. The Legion takes care of their own.
I cannot stress how hard this is going to be. Every night there is bed checks to see who has deserted at night. If you make it their training continues in Central American jungles of Gianna. The jungles are so bad that most countries don't send in their military to train their very long. But, the Legion has a permanent location there. There are many jungle diseases that have not even been classified yet you will encounter.
You will be sent to the worst part of any fighting that the French government has to do. Remember to them you are an EXPENDABLE foreign citizen and of no concern to them. That is why they don't allow their own citizens. Just think about it... They send you in when they don't want to endanger their own troops.
But, being the same. If you survive you will become something that many have tried and few have completed. You will be a Legionnaire. They were described as Devils, not Men.
If you have an honest desire for pain and suffering more than you have ever experienced in your life for the next twenty year, reconsider it again. Seriously, it is more harder than you can ever imagine both physically and mentally. You have to be willing to give up your life and let someone take over all your thoughts and actions, without question. If you have to think about it you are not ready. I would strongly suggest you reconsider this idea.
If you want military training try the Marines. They are easier and they won't try to kill you, they let the enemy do that for them.
I think that Man vs.Wild did a segment on the Legion. Try to find it and watch it for more information.
But, really reconsider it. Think of it this way. What is the most disgusting thing you can imagine eating. Let's say fresh dead rabbit eyeballs that are still warm that you cut out. Running twenty miles in the hot summer sun. Well, not even close.