Board Thread:Questions and Answers/@comment-24.77.5.38-20140502202633/@comment-6697950-20140502203805

This, along many other questions has already been answered on http://swordartonline.wikia.com/wiki/Thread:28038

Quote:

"Kirito intentionally did not tell her the true reason why he was transferring his account to GGO to keep Asuna out of danger. As far as she knew, Kirito was only doing Kikuoka Seijirou a favour by investigating something in the game, but she did not know about Death Gun or that people have been killed."