Ahaa, so there was no anyway chance impress her or gain any trust and she double reads anything what Gilbert/Tolbar says and reads any vile or dark things from it (basically color everything black). Even if he had walked unmasked and told real name (which may as well be suicide this point as she may recognize his last name) and would had thought sheathe his scimitar when he started path of diplomacy. I guess also that even showing his ring would be meaningless (not that he plans to, as said he plans stick in shadows in general about his connection to his father and other siblings).