A topic from AEG's L5R CCG Rules forum, copied for Oracle of the Void from a copy of the forum saved in October 2015, so pages it didn't save are missing. Players' names are left out; the rules officials are named. Rulings are as they stood on these dates; later rulings, the rulebooks and the Rules Archive may differ.
A player, 19 February 2008
Determination Dark Virtue Reaction: Before you announce an action, target one of your Samurai: The action can not have its effects negated or have its targeting changed. After the action destroys any Personality, remove him from the game.
Loyal A Personality with the Loyal keyword cannot be controlled by a player who does not share a Clan alignment with that Personality - either by bringing into play or by changing control.
Can I use determination to gain control of a Loyal personality without my faction alignment (with cards like Show of Good Faith and Hantei)?
Zen Faulkes (rules official), 19 February 2008
Can I use Determination to gain control of a Loyal personality without my faction alignment?
No.
http://rules.l5r.com/Glossary_C#Cannot: "When found in game rules text, the phrases 'cannot' or 'can only' apply to the legality of doing something in the first place; they do not imply that doing that thing is merely negated."