Advice regarding tax laws in Belgium

Seeking advice from those in the know regarding tax laws in Belgium please.
My wife has been offered a permanent job by a large pharma company there with a basic salary of 100,000 euros, however having done some online research I note that the 50 percent tax bracket kicks in far earlier over there than in the UK, coupled with this I note that social security is deducted at source at a rate of 13.07 percent and that each region has municipality tax ranging from 7-9 percent (company is based near Antwerp).
However I was reading last night that there are tax breaks for those working in a research field (she is a toxicologist) and also some breaks relating to having children in private education. We have a 10 year old daughter and my wifes intention is to send her to a European school in the area which I believe falls into the category that allows some recompense for these costs.
I need to better understand the ramifications of the above ,I am not convinced that she will be financially better off as the salary is a 25 uplift from her current UK job but the school costs negate that due to them being 25 percent higher. For clarity , the family home in the UK will have to be sold and thus her intention is that she and my daughter live in Belgium and my daughter attends the European school, we do not own any other property in the UK and the job in Belgium will be her sole source of income aside from a small rental return from a share of her fathers home she received after his death, this will be subject to UK tax I assume but may have ramifications on her Belgium tax return?
Any help and advice would be much appreciated,

I hope someone can give you some pointers but I would urge you and your wife to take some "heavyweight" personal tax/financial advice. Will your wife be tax resident only in Belgium or also in the UK. What about you? There are rules to prevent "double taxation" but someone needs to know what action needs to be taken to ensure liabilities are correctly calculated and reported, and any reliefs claimed.

What is the impact of all of this on any state and private pension provision (in both countries)?

I would be very surprised in the recruiting company doesn't have a firm of accountants that it uses to assist senior people - especially with regard to those moving cross border. It's possible that, if your wife takes the job, they might provide something like that as a benefit in kind.

I took a job with a company in Berlin first wage packet was a real eye opener, 50% tax, plus unification tax, and some sort of health care tax that I would never be able to use! I ended up working as a contractor.

As has been said talk to an actual specialist, the new company should be able to appoint a tax specialist and foot the bill!