"When/if a woman has guilt she will look away quite often, now before she gets back think to yourself how often you and her lock eyes. Think about what her normal mannerisms are with her eyes, does she lock for 20 seconds and then glance away, etc. Compare to when she gets home, monitor for a few days and see if there is a permanent change.
"Killing" her with kindness could also force out a guilt trip "
Mens Rights Activists to the rescue!