As long as you're adopting your Belgian Tervuren from a reliable source, you can safely expect a socially healthy dog that will give you just as much love back as you put into him or her. The breed, however, does have a few relatively harmless quirks when it comes to other people, and as always, you need to consider if your home and lifestyle are right for the dog. These Tervuren's social quirks are relatively benign, but they still warrant consideration.
The Belgian Tervuren, being of Shepherd lineage, tends to be a sociable, loving dog who will remain devoted to their owner. When introducing other people into his or her life, though, one should keep in mind that all Shepherds, the Tervuren perhaps more so than most, are above all else, extremely protective of the people that love them. It's only natural that a Tervuren won't immediately trust everyone he or she comes in contact with and may require an extended "warming up to them" phase before being comfortable around the new person. Hostility, however, is not a common trait for the breed. A Tervuren that is actively dangerous towards strangers has probably suffered neglect or abuse in the past and most likely will require special training.
Young Tervurens tend to be incredibly shy for a period of roughly four months before they develop the confidence and protectiveness they'll carry through the rest of their lives. Some Tervurens carry this trait on into adulthood, but the dog's curiosity and love of new experience will eventually win out as long as they're regularly given human attention and opportunities to meet people.
Tervurens love living with large families, so close friends will be welcome additions to their lives as long as they're properly introduced and the person gives the dog some attention every time they visit. Tervurens are known to get along well with children. The breed is smart and loving and can safely be left alone in the room with most children over the age of four. However, getting a Tervuren solely as a dog for a child is not preferable. Remember that a Tervuren's intelligence is comparable to that of a five year old child, and the dog will need human adults to give them proper training and education. The dog's high energy and playfulness, though, do make them fine companions for healthy children, but proper care and training for the breed is unusually high maintenance and best handled by an adult.
Like most breeds of Shepherd, the Belgian Tervuren tends to be a friendly, approachable, but protective dog. Before bringing any dog into one's home, though, the individual animal itself needs to be carefully evaluated. The way the breed tends to act is not necessarilly the dog you'll get. Make sure to ask all the important questions when adopting the pet. Tervurens need an unusually high amount of human attention in their first weeks, so if they spend their first month cooped up in a cage with no human contact, they may be incredibly difficult, even dangerous, to introduce to new people. If obtained from a reputable breeder and raised properly, though, the Tervuren can be as open to meeting new people and as safe around children as any other breed.