As long as you meet the eligibility criteria, you won't be required to pay tuition fees in your first year, even if you fail one or more papers.
Fees-free entitlements after deleting or withdrawing from a paper/s
If you are in your first year and leave partway through the year, you will not need to pay back the fees for papers covered by fees-free. However, your future fees-free entitlement may be affected depending on whether you delete or withdraw from your papers.
The Adding, deleting, and withdrawing from papers page has more information on how your fees-free entitlements may be affected and due dates to delete or withdraw by: