What does it mean exactly trust enabled flag?

What does it mean exactly trust enabled flag: ena under show mls qos
interface?

SW1#show mls qos interface gigabitEthernet 1/0/1
GigabitEthernet1/0/1
trust state: not trusted
trust mode: not trusted
trust enabled flag: ena
COS override: dis
default COS: 0
DSCP Mutation Map: Default DSCP Mutation Map
Trust device: none
qos mode: port-based

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Received on Wed Apr 22 2009 - 19:52:03 ART