1. Honestly -
Meaning: I’m not aware of that information.
Example: My friend Marissa lost her algebra book. She can’t find it anywhere.
Marissa: I can’t find my algebra book anywhere. Have you seen it?
Me: I don’t know (where your algebra book is).
2. Apathetically -
Meaning: I don’t have the answer and I don’t care enough to find out.
Example: My mom keeps asking me what I want to do with my life career-wise and I’m tired of her asking.
Mom: Don’t you think it’s time that you figured out what kind of career you want to pursue? All your other friends have. What do you want to do?
Me: I don’t know (and I really don’t care).
3. Apologetically -
Meaning: I really wish I had the answer but I don’t.
Example: I borrowed my brother Joe’s car to go to the store. When I came out of the store, the car had a dent on the door.
Joe: What happened?
Me: I don’t know (how the dent occurred but I’m really sorry).