Trust and lies

You promise to meet me for dinner at 7. We say that the promise normally makes it appropriate for me to trust you'll show up at 7. But that's not quite right. What is more appropriate to trust is that you'll meet me for dinner at 7 or have good moral reason not to be there. This point applies even if I know that you won't have such good moral reason. For that you won't isn't s matter of trust of you, but of prediction.
By the same token, if it can ever be permissible to lie, and you assert something, I never ought to trust you that you are being truthful. Instead at most I ought to trust that you either are being truthful or have good moral reason to lie.
So if it is ever appropriate to take it on trust alone that you are being truthful, lying is always wrong.