Well, "Ned. Wapenmagazijn" stands for "Dutch weapons store", surely some kind of retailer in Holland.
"V/H.S. De Jager Haarlem" I think means "For/ HS(initials)The Hunter ( a common dutch family name) Haarlem (a town in Holland)" and is probably meant to name the client who ordered the gun and his hometown.
This gun, of very high quality, was made in Liege, Belgium, for a Dutch customer.
Traditionally, Dutch hunters ordered their guns in Belgium by way of a local retailer.
Greetings,
Livinus