My 'honorary' niece is 5 years old. The other day I made a comment about how she was lucky to have a mommy who is always honest to her (referring to the fact that her mother was upfront and honest about things some parents are afraid to touch on, such as where babies come from, who her biological father was, or the truth about Santa Claus etc.). She responded to my statement about her mother never lying by asking "like you lie?", implying she thought I would lie to her.
This is the second time something like this has happened. In both cases it was a very honest sounding statement, I don't think she was trying to be mean or imply anything, she just honestly thought that I would lie to her. This upsets me precisely because I go out of my way to be very honest with her like her mom. I always give honest answers to important questions and never try to avoid answering them. I also try to never tell little white lies to her. In general I believe I'm far more honest with her than most adults would be as it's been a very intentional commitment to be upfront with her.
My only explanation for why she would think I would lie to her is because I will play games or make believe with her. For instance I'll pretend to have fallen asleep, so she can jokingly 'wake me up'. I may also do something like pretend to eat a piece of plastic food and jokingly insist it was yummy when she asks what I did with it, even though she knows I couldn't have eaten it and will find where I hid it (or I'll show her if she didn't). I'll make up games and jokes along these lines often, but I've always believed she was at the developmental level where she could clearly understand the difference between this sort of make believe playing/joking and serious situations where I would always tell the truth.
I've also occasionally given her some mini logic puzzles to challenge her, such as betting her I could walk on water and asking her if she knew how (by waiting for it to freeze). In these sort of situations I'm using some poetic license with the truth for the sake of challenging her (i. e., ice is technically a different state then water), but I haven't done that sort of thing often and I always explain what I meant to her if she couldn't figure it out. Again I wouldn't have thought she would consider that to be lying.
Why would she consider me capable of lying to her when I go out of my way to be extra honest with her? If my games are confusing her how do I help her to understand the difference between make believe games and joking and serious answers so she knows when I'm being honest?
I have told her that sometimes I exaggerate when were playing, but that I'd never lie to her in reality. I've also always told her that if I promise something is true then it is, that I'll never joke about a promise. Is there anything else I can do?