Originally Posted by
Koby
I would by a refundable ticket for the 6:31 Thalys train. If you don’t make it, get your money back at the Schiphol train station and buy a ticket for the 7:09 IC train. (No need for advance reservations - and you can ask for a ticket all the way to BRU airport I think.)
AFAIK you can get a ticket to the airport regardless of which train you use.