Decline Message

I am wanting to change this “This transaction has been declined” on the last page after a person checks out and order is failed or declined card will show this in a bright red box background. I can not find in languages the exact phrase and tried one word or another and everything came up but the one I need. The background I am sure is in the css file but where can I fine “This transaction has been declined”

Orders->Order statuses->Declined

That part is no problem I did that and still there is a different decline that comes up on there cart page with a red background, that message is what I need to change