I have a friend called Marijk. Grew up in England but has a Polish mother. Never caused any he problems. Generally, you only need to tell people a couple of times how to pronounce something and if they're family/friends they should have the good grace to pronounce it properly.
DH's Flemish cousin is a Marijke - pronounced Ma-rye-kuh. Yes it's a diminutive of Maria (the 'ke' meaning 'little' (not ka as in S Africa) is added to a lot of female names - most Flemish women over a certain age are called Maria (both his grandmothers!) and all sorts of diminutives/derivatives have occurred over the years. In the past the Catholic Church would not allow you to actually be baptised with anything but the formal name but now they do. Hence lots of Marijkes, Mias, Meikes, (latter my fave - pronounced mee-kuh - only somehow softer than that in a Flemish accent).