As a monolingual English speaker, I got work in Antwerp in 2005. Mind you, I’m in IT, where the professional language is English. Depending exactly on what job is, and where you work, you should be able to thrive with English.
However, the Flemish authorities are a bit fussy about their language, so I would strongly advise you to consider learning it, if you decide to live there. I did that, & in fact picking up languages got to be a habit, so I now speak five, with varying levels of ineptitude.
Secondly, when looking at Belgian salaries, if you’re quoted an amount per month, never forget their bizarre habit of paying you for 13 months a year, sometimes 14. You get an extra month’s salary for summer holidays, and some employees give you another one at Christmas.
I found that Belgian taxes are fairly high but the cost of living was fairly low, so I had enough money to live, with some left over.
I found Flanders a great place to live, and look back at my time in Antwerp and Mechelen with fondness.
Originally posted on quora.