Welcome back to the Wefugees Community and thank you for reaching out to us again.
As far as I remember, you raised a very similar question a while ago, right? I will paste the respective link here again.
Regarding a second asylum application, a colleague explained also in this thread
The obstacles are quite high by law, that is, the BAMF checks very strict if there are reasons at all to open up a new case. It can only be about new reasons, that have occurred after the first application was over and you have to file the application within 3 months after you get to know about the new reasons. Another example is if the law (in germany or in your home country) has changed in your favor and gives you new arguments, why you need protection.
The marriage process is not connected to the asylum procedure - even as rejected asylum seeker you can marry in Germany. However, keep in mind that you need to provide a number of documents to the authorities. Please see, for instance, this thread for more information.
I hope this helps and please don't hesitate to get back to us with any further questions.
All the best,