Do foreign people have another mentality in comparison to the Belgians?

Yes, African people are most of the time more difficult to adapt because they have another culture, in the most parts of the country they aren't used to go to the school and so it's more difficult to teach them something and especially the foreign language, Dutch. People from Russia and other East-European countries have a more similar culture and it is easier for them to start at school, because they have a culture of learning.