Yes, one still there working for her you have never met…and who may fear for her job if anything but sunshine and rainbows is said and it gets back to her. Or it’s fake. Don’t trust anybody without verifying whatever they say.
Plus that, if there is any possibility this nothing in writing scheme violates German law or your student visa, it.s you who will suffer the consequences, trainer knows that.
Wonder if anything in writing regarding specifics of the position and payment violates the terms of the EU student visa???