Bullmastiffs are one of the most faithful and devoted dog breeds that you can find, and seeing that they are a part of the species known for its loyalty that is saying a lot. They are extremely friendly and gentle, which is probably not something that one would think considering their impressive size and the fact that they are obviously overflowing with strength and vigor.
They have been bred to help gamekeepers detect and capture poachers. Bullmastiff was supposed to catch a poacher, pin him to the ground and hold him there until the gamekeeper arrived. They were not supposed to bite, and instead they used their weight to do this. The habits they developed while they were doing this made them excellent guard dogs. They will never bark except when they are trying to raise an alarm and alert their owners of intruders. And they are known for their devotion to their owners and willingness to put themselves at great risk to protect their master. And even though they are incredibly fierce when doing that, at all other times they are the cuddliest 120 pounds of flesh that you will ever see.
They are very friendly and love playing around with children or adults. You just need to make sure that they socialize a lot when they are young, with people as well as with other dogs. If they don’t get used to the presence of other dogs they might learn to consider any dog that comes on Bullmastiffs territory an intruder and they will become hostile.
Because of their intelligence they are very easy to train if you have developed a normal relationship with the dog. You need to be confident and assertive enough for the dog to realize that you are his master. If you appear to lack authority and determination the dog will not come to respect you as his pack leader and this will lead to him becoming too willful and disobedient. You shouldn’t treat him harshly in order to show him that you are the boss, you just need to assert your dominance by displaying your willpower and the faith in your unshakable authority.
Once you have managed to establish that type of a relationship Bullmastiff will be extremely obedient. They are great at recognizing the intent behind your tone of voice and will take your praise or criticism seriously. Use positive reinforcement when training them, commend them verbally and reward them with a treat whenever you are satisfied with their reaction to your commands, and scold them in a low voice when you are not.
They are an extremely energetic breed and will need a lot of exercise, take them out for walks whenever you can and if you have a yard, by all means give them free access to it as they will relish the opportunity to have a good run every once in a while. Try not to leave them alone for too long, the strength of their bond with their owners is such that they will feel abandoned if they don’t get to be next to their owner for a long time, and this will have a negative impact on their behavior.