Expressions to deny something:

-No way!
-Absolutely not me.
-That's not my fault.
-I'm not the person.
-I certainly do nothing.
-I didn't do that.
- Of course, I didn't do anything.
-I swear, it wasn't me.
-It can't be possible
-I'm out of here.

Expressions to admit somethings:

-I'm sorry.
-That's my fault/mistake.
-Yes,I did.
-I'm the person. sorry..
-Sorry for..
-Forgive me for..
-I did that. Please, forgive me
-I admit that.../I admit for..
-I know that's my mistake. Will you forgive me.?