My conscience doesn’t allow me?

[flytothesky]

Hi~~ Would you help me how to say this naturally please?

A: Sorry, I don’t think I can handle it.
My conscience doesn’t allow me.

B: It has got nothing to do with conscience.
ⓐYou go too far.
ⓑYou have gone too far.
ⓒYou think too much.

A: How can I cheat on kids to take their small money?

B: Just once, come on.

[sushuma]

(I am not a teacher)

I would just change it to "My conscience won't allow me."