What information does Gilthanas bring specifically to Laurana?

The information that Gilthanas brings specifically to Laurana is regarding Tanis. With much more compassion than was shown by Kitiara, he explains that Kitiara and Tanis are lovers, and that there is no doubt at all about that. He further explains that Kitiara was asking permission for Tanis to be brought high into the ranks of the army for information on the Green Gemstone Man.