"Master!" Nie Fan cried as he stared at Su Yu with his eyes wide in both shock and disbelief after he heard what Su Yu has said. That he (SY) believes in Duan Tianyang, and he (SY) even asked Duan Tianyang how much does the other remember.
Well, Nie Fan feels flattered that Su Yu said that he trusts him, too. Because Nie Fan knows that Su Yu met him, though only very much later after Su Yu has met Duan Tianyang. And Su Yu met him, Nie Fan, only after Su Yu has been turned into a demon from being schemed against by poisoning Su Yu through making him drink a pure demon's blood. Thus, Nie Fan really feels touched that Su Yu trusts him even after all this time.
