Dear @honesty,
Welcome to the Wefugees community.
In order to answer your question properly, it would be important to know what your home country is and if she is living in Greece legally or not. Then, we can have another **** for you.
Please have a **** at these following threads, as questions around getting married in Greece have already been answered on our platform many times :-)
Can a refugee get married in Greece with an EU citizen?
Can I get married in Greece although my asylum case is incomplete?
How to marry in Greece ?
Maybe the answers on these threads already answer your question. Otherwise, please get back to us with the information and we can check options you two have. Also, please bear in mind that if she is in Greece illegally, she may face deportation.
All the best,
Isa