The sentece is: Vincet knew enough to have decided that no one in it could ever be trusted.
present perfect: An action or situation that started in the past and continues in the present.
simple past: An action that occurred in the past and which does not extend into the present.
Vincent knew enough to have decided
The sentence is correct.
Vincent learnt something in the past which does not extend to the present, his learning has occurred and has now ceased. Vincent made a decision in the past, but that decision continues into the present and is still now valid. Therefore, the combination of past simple (does not continue) and present perfect (continues into the present) is an accurate combination.