Bubbly My Grandma would say NEVER trust no-one NOT even your Grandma!
Use common sense, remember: too good to be true?
What I do is I ask questions about the place they say they are for example: an intellectual man from netherlands, I asked him what was interesting in the Van Gogh museum, he had no idea! another an Italian man I asked him about his favorite food and so on...
If he rushes to exchange email addresses, be suspicious, get to know them better in this site.
RE: Friendship
“Friendship always benefits, love sometimes injures.” Semeca