His Weakness:
Deep down she knows showing her love, furthering their relationship will only cause him harm.
Deep down she recognizes their mutual affection for each other could only be exploited by their enemies to further some hidden, horrible agenda.
She knows she could never live with herself if she caused him injury at her expense. Because, she knows, he would give himself up in a heartbeat to save her. Recognizing this, it scares her.
She could not bear to be a pawn in some evil game that could hurt one or both of them.
No, she refuses to be his weakness.
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Author's Note: Holy Cow! I wrote a drabble! This is something I've never managed to complete before. HA! Pathetic I know. :D
Oh, and if for some reason you feel compelled to let me know how my first foray into "drabble writing" went, by all means, leave a review!
Cheers,
Lemons