If you are thinking about looking for a job in Belgium, you can proceed in different ways. An efficient way to find work is to contact companies directly (networking). You can also register with the UWV as looking for a job in Belgium. The UWV will make sure that your CV is made available to Belgian employers. You can also register as a job seeker with one of the employment services. In Flanders at VDAB, in Brussels at Actiris, in Wallonia at FOREM and in the German-speaking community at the Arbeitsamt [employment office].
If you have found a job in Belgium and then become unemployed again, you must apply for unemployment benefits (with some exceptions) in your country of residence, the Netherlands, at the UWV. Even then, you can look for work in the Netherlands and Belgium again.