What can you expect?
Before you go to look at a puppy and fall for that irresistible face, please stop and think whether this is really the breed for you.
A good Boerboel with the right owner is a joy, however, Boerboels are most definitely not the dog for everyone. Owners need plenty of dog experience, preferably with a large guarding breed. A Boerboel needs a firm hand and strong leadership.
Consider whether you have the time and commitment to own a large, guarding breed. You will need to spend a lot of time training and socialising your dog. A badly-behaved big dog is at best a nuisance and at worst a liability. Your garden must be securely fenced to avoid misunderstandings. Most of these dogs are territorial and, when mature, will not allow strangers onto the property unless you are there to give permission. This includes the postman and Parcelforce.
You must be able to give your dog plenty of exercise, preferably off-lead where you will not encounter strange dogs. Boerboels are not generally dog-aggressive but most males will not tolerate a strange male.
Boerboels are intelligent and thrive on being part of the family. If you are out all day, it's probably not the right breed for you. A bored Boerboel will take your house apart.
Think of the practical considerations of owning a large dog - a big male will not fit in an average family car! They all eat a lot, defecate a lot, shed and snore, many drool and some emit enough gas to be classed as a chemical weapon. Big dogs equal big vet bills, a good insurance policy is highly recommended!
Lastly, if you don't have previous experience with guarding breeds, please think carefully - 70 kgs of dog requires a lot of leadership and you should be prepared to put in the work to make sure the dog is trained and manageable throughout its entire life.