I think its bc when they first meet in the bamboo forest (when she was in her girl for) she was injured and he healed her and at that time she was bleeding from her shoulder so I think he somehow remembered her blood and when you held her wrist he recognized her blood bc the blood was in his hands I guess??
Or he could feel his energy he shared with her?
To me he got suspicious after he caught her when she was falling and he saw the way she blushed. His suspicion increased after that because all the little hints that showed they were one person, suddenly became obvious.
Can someone explain why he got suspicious after holding her wrist? I might’ve forgotten some parts