A man of such obvious and exemplary charm must be a liar - Brookner

ONE SAYS:

This is not a causal statement yet it is written so. "If it is raining, then there must be water" is a good use of the word must. Brookner should have chosen "likely" or "most probably."

Witty response: the root of charm is compliment. A "liar" does not speak truthfully. Perhaps then the object of focus is not worth the compliment/charm- then it would be a lie.

I SAY: i simply think Brookner meant that guys who try too hard make it obvious that they are trying to only impress ! So not only is he lying to himself of what he is trying to present but also lying to his audience

whos right in this one ?

I think "ONE SAYS: ... " is correct. I understand what you are saying, and poetically your interpretation is a good one. However, does Brookner mean that every single man with "obvious and exemplary charm" is a liar??