1. Fear of a capricious state can cause survival-motivated compliance which can appear as "trust" in coarse measurements. Meaning, you simply do fewer of those things that would provide opportunities for distrust in contexts where that could happen.

2. In a relatively severe, but consistent regime, the high penalties for violating trust in everyday cases (crime) act as a deterrent.

3. Fear may cause people to be selective and mindful about their social associations based on stronger proofs of trustworthiness. You might tell a Hitler joke to someone you have used more energy/caution to "vet", but avoid being too casual in environments of undetermined trustworthiness.