Get some rest
Lex used his sixth sense, his instincts and his own better judgment all to determine the veracity of what Cassandra was saying. According to his own judgment, Cassandra did not seem like she wanted something from Lex, or wanted to set him up for something. Instead, her entire being reeked of objective neutrality. If Lex were really forced to assign an emotion to describe what she may be feeling, it might be akin to the feeling of a skillful jeweler upon discovering a unique gem - wanting to ensure the gem was polished and attached to a work that will make it shine like it deserves.
Ultimately, Lex could not detect any reason to doubt her, and the feeling emanating from deep inside of himself won. He stood respectfully in front of her and bowed slightly.