Dear
@Ousman,
thank you for your question.
In your situation it would be best if you get married in the Netherlnads and then your fiance applis for family reunion for Germany.
You could do a second asylum in Germany but then Germany will not process your case as the Dublin Regulation will apply, that means that NL is responsible for your case.
I hope I could help you, if you have further question please feel welcome to use the platform.
Best regards,
Nilab