+0

1. I'm not confident what to say.

2. I'm not confident about what to say.

3. I'm not confident on what to say.

4. I'm not confident over what to say.

Could you tell me which ones are correct?

I think they're all correct...

+2

1. I'm not confident what to say. OK

2. I'm not confident about what to say. Correct, best.

3. I'm not confident on what to say. No

4. I'm not confident over what to say. No.