Here's an idea... I have multiple last names after marriage!

So I learned about name change after marriage thing.
To me it's a foreign concept. Our naming system is different entirely.
In our culture, you have your given name, then your father, then his father, and so on as much as you like and end it with the surname.

Like, Alex Jonathan Frederick Alpacino xD (you can put "son of" between each name)
Of course I made it as an example.
In her, you keep your name after marriage. I've never seen anyone who changes except Christians in Egypt.

Anyway, our last name is never really last name. I have a family nickname, a family name, and a tribe name.
In fact in my ID I have two last names, but only one in my passport.
But I never go with the name in the passport, it's a nickname not a real family name. Everyone knows me by my tribe name.

My question is, since my fiance badly wants to carry her tradition about this, and wants to use my tribe name since it's a lot easier for the non Arab tongue to pronounce, can she change her name after marriage to another name based on my national id from my country, choose a name that does not match my passport, or is it obligatory to use the same last name in my passport?

Your passport is your identity; everyone is going to assume that what is there is your real surname. Perhaps you should have exercised a better judgment when obtaining it. Your English is good so you should have known better how the rest of the world operates. Get a new passport, problem solved.

Shorthairthug is right. For all official purposes here in Poland, the only name you are allowed to use is the name on your passport. You won't be able to change it here in Poland until you become a Polish citizen. or you change it on your passport.

For non-official purposes, you can go by whatever name you like.

oh if only you know the history behind this XD
It's something my grandfather's generation did and we're trying fix. Sadly I can only do it from within my home country and I'm an expat, and it would take me a WHOLE month of processing. Unlike the west, any changes to your name is a very complicated process.

Because of that, let me rephrase the question:
Can the girl change her last name to anything else besides husband's?

She can only change her surname to her husband's surname.

I don't understand the concept or many surnames, or one surname in the passport and another in your ID, how can it be different? Surname is a surname. You get it when you are born and it should be written in your birth certificate. It should be then the same at your school diplomas, ID and passport. I'm pretty sure as a foreigner you will need not only passport but also birth certificate to prove who you are. The surname must be the same. Only then the woman will be able to get your surname. She cannot just pick whatever she wants. If that was the case then nobody could control who is who. Everything must be official.