Root hints are DNS data stored in a DNS server. The root hints provide a list of preliminary resource records that can be used by the DNS service to locate other DNS servers that are authoritative for the root of the DNS domain namespace tree.

Source

This just means that your local DNS server doesn’t need to use the root DNS servers to resolve domain names but instead uses other authorative DNS servers in the internet to resolve your queries. So anyway you have to trust an upstream DNS server owned by someone else in the internet. There’s no way around it unless you use hyperlocal.