as some have said business cards do actually carry more weight than they do in the west afaik
But while it would've been nice if Natori just completely trusted Asako in that situation, it is nice to actually see Natori being the one properly troubled for a change. Like up until now most of the reassurance came towards Asako and her insecurities (the only Natori one was the previous gf one I think) so from that regard it's nice to see that Natori isn't as perfect as he was made out to be
And on another plus, it's nice that Asako immediately confronted Natori about it and they were able to share their thoughts, rather than let this misunderstanding drag on
edit: Actually,
@phosphylite while yes the dude did back off after Natori confronted him, his smug grinning seemed to imply that he wasn't completely backing off, so I can understand Natori's frustration at that part (plus the dude challenged Natori's ability to protect Asako as well)