What does "Secure your fare" mean?
When you want to book a ticket online, but need a bit more time before confirming your booking, you can secure the fare for 48 hours.
On the flight selection page, click on the button 'Secure your fare' and complete your reservation. You will receive an email with more instructions and have 48 hours to confirm or cancel your booking. A cancellation fee will be charged if you don't take any action within 48 hours or cancel your booking.
More information can be found here.