For your information, a confirmed onward/return tickets (where applicable).

The granting of visit passes to visitors is determined by the Immigration &
Checkpoints Authority (ICA) officers at the point of entry. Visitors must
satisfy the following basic entry requirements before they can be
considered for entry into Singapore:

a) A passport with at least 6 months validity
b) Valid Singapore visa, if applicable (refer to the Visa Requirements page
for more information)
c) Sufficient funds to last for the intended period of stay in Singapore
d) Confirmed onward/return tickets (where applicable)
e) Entry facilities to their onward destinations, e.g. visas.
f) Completed Disembarkation/Embarkation Card
g) Yellow Fever Vaccination Certificate, if applicable