It could be surprisingly hard to counter Plain Stupid. Even by heroic measures. - Lois McMaster Bujold

“Other than that, how was Kiril Island, Ensign Vorkosigan?” inquired the Count. “You didn’t vid home much, your mother noticed.”
“I was busy. Lessee. The climate was ferocious, the terrain was lethal, a third of the population including my immediate superior was dead drunk most of the time. The average IQ equalled the mean temperature in degrees cee, there wasn’t a woman for five hundred kilometers in any direction, and the base commander was a homicidal psychotic. Other than that, it was lovely.”

The limits of trust depend much on whether you mean to do business more than once.

All sorts of men had the capacity to kill for the convenience of their betters; though usually, the only spell required could be fitted in a clinking purse.