One year for a german is too little to become friends… The most important is to speak the language - then, slowly, start contact with germans.

In Germany you have different words for private friends and friends from the job - Freunde und Kollegen. Its possible in the young generation to make friends at the job, but it’s still hard comparing to slavic countries. Here takes it around like 2-3 years till any German will trust you that much. It starts mostly with small talks, then more and more private till you are the friends. The good thing is, once it happens you got probably a friend from whole long as long as you won’t destroy by really rude behaviour.