I answered their questions 'to the best of my knowledge'. [=I gave the best answers I could based on what I knew, but I might have answered differently if I had known something else]
No one arrived late 'to my knowledge'. [=I am not aware that anyone arrived late, but it is possible that someone arrived late and I don't know about it]
They went on vacation, 'safe in the knowledge' that the farm would be well cared for while they were away.
(..) Unit was leased for ten years, pre-paid in full. The contract is in the name of a Miss Hester Mofet. So nobody's been in here since ? Not to my knowledge. Privacy is a great concern to my customers. Yes. I won't disturb anything, I promise. I'll be outta here before you know it. - May I help you? (..)1991 The Silence of the Lambs
(..) - No. No, you ate yours. You send that through now. Oh, Agent Starling, you think you can dissect me with this blunt little tool? No. I thought that your knowledge... You're so ambitious, aren't you? Do you know what you look like, with your good bag and your cheap shoes? You look like a rube. (..)1991 The Silence of the Lambs