US Army, Final letter to girlfriend.?

I enlisted into the Army as 89D, EOD Specialist. (Explosive Ordnance Disposal). When i get deployed and i wright the letters to my family and girlfriend (the letters they would get if i were to get killed). Do i give them the letters before i leave and tell them not to open it (this way i make sure they got it), or just keep them with me and hope that they would get them? I don't mean to be negative, but im just being truthful with myself. Thanks.