@icarushector
well, considering how the story was framed so far she was likelly given the role of meeting him when he was reborn and giving him the glasses from a god or some type of guild of reborn people.
she said she "have to give him the glasses" and "that is how everyone sees the world", so they might not really be anything rare.
consider :
1. she knew he was going to apear there. who have the power to predict that ?
2. she is also an outworlder, not some random person from this world. so she is relatable and a good fit for the role as his tutorial to this world.
as for her info dumping on him, most is likely is public knowledge. But it is still knowledge from other countries. from that we can determine that the world likely have a pretty good information system or she is REALLY well informed. Considering she's a barmaid, she is likely part of some type of guild or was given that information by someone who is in the business of information....or it's just bad writing....
for now we have to suspend our disbelief until we get more info it's only the second chapter after all.