What is trust when you check an Operator in Arknights? This shows your relationship with your current Operator and how much trust they have placed in you. Increasing your Operator's trust lets you gain some benefits and you'll be able to unlock information about your Operator as well.

What does Trust do?

If you check below your Operator's Attributes, you'll see their trust. If you press the bar, you'll see the stat bonuses that you can attain. Increasing your Operator's trust will provide the following benefits:

Gain extra Stats once you reach 100% trust
Unlock more lore through Operator Files at 25, 50, 100, 150 and 200 trust

How can I increase Trust?

In order to increase trust, you should use your Operators whenever you play the game. Completing different episodes with them will increase their trust gradually. Once you have unlocked the base, you can increase trust by letting them work there as well.