You basically have to check their profile and see how much thanks or what is their rank on the website meaning if they helped a lot or not. Some people provide tools from the web or trusted answers so it depends
I’m pretty sure that it’s the second one. I definitely know that it’s not the last one
To confirm his high opinion of the woman ,speaker supplies - no evidence at all.
A to give credit to the source.
His friends were laughing at his use of English and, after taking in the pain, he too was laughing, He learnt English by his mistake. His reaction to the event made him accepted by his new country.