I am pleased to answer your questions as the following:
1- in this case, Am i guilty that i don't want to go with her because she want to make a complain against me as i don't want to go with her?
You are under no obligations to go and in fact a very wise not to sign anything she asks you to in this matter.
2- Me and my wife are foreigners which law to be applied our homeland law or german law?
What is your nationality? Do you share the same nationality? Where did you get married?
3- my wife joined me as family reunion, if i divorce her then she will not be able to be in germany any more?
That depends on how long she has been here and whether she has her own means to support her stay here.
4- she wants me to go out from apartment and i can't rent another apartment, Am I mandated to leave apartment?
No, you are not. You two either find a compromise or ask a court to give the place to either of you.
5- what is the cost of divorce in Germany?
Court and lawyer fees depend on the assets involved in the divorce. It will easily cost a few thousand Euros.
6- what will happen if we follow the German law and what are my rights also wife's rights?
Happen? In case of a divorce?
All the best