You transfer your emotional rating in damage to yourself. Person A is trying to heal person b and they fail. They still heal Person B, by transferring those wounds to themselves equal to their emotional rating. If person A has an emotional rating of 1, they would heal 1 from person b, and take 1 damage to themselves. If they have a 0 or less, on a fail, they don't heal person B because they have no emotional rating.
Does that help?