There is nothing worse than destroyed trust, unless, perhaps, it's the annihilation of hope; a combination of the two is a complete sucker punch. I'd like to know the motive, but at the same time, it really doesn't matter. In light of the past few days, maybe it's karmic justice for the collapse of my latest relationship...
Back in the realm of simple concepts, how about this one: don't lie to me. I am a fundamentally and sometimes brutally honest person, particularly with myself. I have very few illusions about anything- but nothing permanently destroys my opinion of somebody faster than catching them in an untruth. This also wasn't just a little white lie, it was a fulminatingly evil story cut from whole cloth.
I've spent my life trying to help people. I despise being the 'bad guy', especially when it's unavoidable. Being gulled, and deliberately so, over something that matters so much to me is way beyond my limit. From this point forward, nothing that is said to me by this individual will be considered credible without outside verification.
Whatever the logic, the damage is done. Next time, fair warning: I come out with my sword drawn.