When someone's trust is in the orange and they will not do anything for you, enter first person mode and aim the gun at their head for three seconds. They will now do things for you without good trust.
Game Shark Codes
Master Code (Must Be On) 0E3C7DF2 1853E59EEE8C6406 BCBCD3EA
Infinite Health DEBD6E92 F8AADD4BDEBD6E9A 6AAA9B1F
Infinite Ammo DE4E515A E0AC9BB5