Marrying a Belgian whiles schooling.Will it guarantee your Permanent stay in Belgium

Every case is judged separately. There is no guarantee that two people with similar cases will be treated identically.
However, if your brother is a Belgian citizen and is sponsoring your education, he should be able to ask at his commune and get some idea of what your chances are and what you will need to produce when you apply to stay.
As a general rule regarding marriages, the authorities have to be satisfied that a marriage is genuine and not just a way to get residence in the EU.

Hi,
As said by Kasseistamper, it depends from case to case. Nevertheless, you can already get a lot of information online, for example:
http://www.expatica.com/be/visas-and-permits/How-to-apply-for-Belgian-ci... http://www.belgium.be/en/family/naturalisation_procedure; http://www.xpats.com/path-belgian-citizenship-expat-trail-guide.
Marrying to Belgian national does not automatically give you a right to apply for citizenship. As I just recently got mine (EU resident), I can give you some more details. First of all I had to be a resident for minimum 5 years (it had to be exactly 5 years since issuing of my ID cart) - as i work here since the move in Belgium (uninterrupted) , that was basically enough to apply. Being married to Belgian did not help whatsoever, as being employed since i moved here automatically means you are socially integrated, economically participate and is a proof of knowing the language. Besides my paycheck statements, birth certificate , proof of payment 150EUR 'registratie gerecht' I didn't need to supply anything extra (even though i did, just to be sure :). The rules for applications are: you need to be 18 years old minimum, you are legally and without interruptions residing in Belgium for the last 5 years (they look at the date of issuing your ID (I had an E-card), you are allowed to reside in Belgium for indefinite (so no temp visas), you know one of the languages (Dutch or French or German ), you can prove you integrated in society and you have a proof of economical participation. That is in short. The smartest way around it is to set an appointment with your Gemeente (Districthuise) where you get all required information based on your specifics. But before you are here registered for at least 5 years, without interruptions, I would think it is close to impossible to even start the procedure. Nevertheless, all what you get in the forum are mere opinions, suggestions. Visit gemeente and get valid, personalized answers.

Agree with kasseistamper. You DO have the RIGHT to ask for citizenship if you are married to a Belgian, however, you must reside in Belgium 5 years before you can apply for citizenship. Now, I say RIGHT to ask because there is NO 100% guarantee you will receive it. Puni isn't totally correct about the "details" he/she has given. He/she took the Naturalization route apparently and that isn't the ONLY route to become Belgian. You would be better off going to your gemeete/commune and find out the real facts and how that will apply to you. I could go on and on about how I obtained citizenship like Puni did, but that's not going to help you unless your situation is identical to mine and it isn't. Good luck.

To be honest that never crossed my mind....economic seeker. You sound like someone who is just trying to find a way to be with your gf and that's all. The other option is she could come to your country to live. Whatever you decide think about YOU and how all this will affect YOU in the long term. Love is a powerful thing, but one needs to be sensible too. All the best!