Beste antwoord door Keuzereiziger
To buy a ticket from Belgium to The Netherlands (or vice versa), you could use the websites www.nsinternational.nl/en or www.b-europe.com. They sell international train tickets payable by credit card.
For trips within the Netherlands the best option would be to buy the ticket at the ticket machine, as they accept credit cards. Unfortunately, the ticket machine will charge you € 1,- over the regular ticket price, because of the throw-away-chip in the ticket.