Could you maybe provide some more details on your situation? I think that would be helpful in order to fully understand your case. The so-called "certificate of no impediment" will be however very important as the authorities ("Standesamt") will ask for it. This is a document which proves that your are not already married. A related question was already discussed here before (https://www.wefugees.de/803188/marriage-without-certificate-impediment-ehef%C3%A4higkeitszeugnis?show=803188#q803188). Maybe you find some for you relevant information in that thread also.