Trying to reassure him that he wouldn't seemed like a bit of a moot point. The truth was that Di held onto Signless' words faithfully, and so she held onto Karkat's capabilities faithfully. Sadly, she didn't have Signless' way with words. She didn't know how to both speak of said faith, and assuage his fears.

"Would you like to speak of what happened?" It was the best she could think to do. Perhaps he might feel a little better if he thought they knew what to expect of him, and what not to expect. To be honest, she was also rather curious.