Hello Bahamian, you know animals have personalities.  It is important to remember what socialization is, what it produces in us and our dogs and how important the outcone is to successful training of guard dogs.  

If you look at the breed standards of these dogs especially my Brazilian Mastiff you will read the words instinctively knows.  These dogs do many jobs including assistance to people with disabilities including epilepsy, diabetes, seizures, strokes and other illnesses including cancer and heart attacks.  The reason why is that our body chemistry changes and they can smell this and alert the person to the upcoming or present danger.  This is also why we socialize our dogs so they are exposed to our world, it's sounds, smells, dampers, joys acceptable and otherwise and in what degrees.  Remember there are levels of danger and levels of defense mandated by law everywhere.  Socialization does not mean everyone gets to touch, pet and play with my dog.  It does mean that when I take my grandchildren to the park I want to be safe so I take my Guard dog with me.  He rides down the slides, plays in the sand box, rubs across the fields with them he tolerates humans around them but is always mindful of what is around us and alerts me to activities beyond my range.  He goes into the rest rooms with my grand son and I know he is safe.  What he doesn't do is act like an out of control fire breathing dragon.  He has learned to control himself and use his instincts to assess the situations we are in and then behave according to what is best.  Your guard dog must learn what and when this is important so they can be safe as well.  I think your female is much stronger than you realize.  Also aggressive is not what you are looking for in a guard dog.  Aggression always stems from a negative such as fear, anxiety, lack of confidence in nature this animal would most likely be run off or even killed.  It is unstable it is a bully.  This is an animal that is out of control an not useful because it acts without duscretion.  

You want a guard dog that has the ability to work with you anywhere anytime.  I can assure you that if you or your fire breathing dragon dog come to my home you will not get in I can also promise you that because of your dog's expressed aggressiveness my Yogi would have to kill it because your dragon dog does not understand accepted behaviors only aggression.  All this is unnecessary.  But if I am at home when you come I can tell Yogi you are entering even your aggressive dog and he will tolerate you.  The difference is you will know he is waiting and watching and if you mess up he will be there.  This is only if I allow you in and give him a command.  

I have used the friend command in the past and I use it today for my grand children to use when they bring friends.  It does not tell your dog be all lovey dove with these people it tells your dig they have permission to be there and interact with you dogs don't interpret words they interpret our chemistry.  I can say friend all day but if I am upset and anxious Yogi is on guard.  So I have to control myself if my chemistry is saying anxiety but my actions are calm and controlled he knows I have a medical situation and help is needed.  There is too much to write here.  As I have said I have Yogi tested he is not aggressive he is protective and wonderfully gentle with my grandchildren and elderly persons.  Allso thr official scaling of ojeriza Is not about how aggressive they become it is a definition of the "distrust" of strangers and how the individual animal uses it.  Some very aggressive dogs are low level ojeriza and determined to be fearful.  So look at your female closely and socialize your digs so they can be the best guard dog possible living a healthy and safe life with you.  Socializing, exposing our companions and teaching them appropriate behaviors saves them from unnecessary euthanasia.