This user commented on my post the same day they created their account and claimed they wanted to trade. We added each other on Steam and agreed on a fair trade. I found the communication to be respectful from boths ends and I was trying to be accommodating, but I did not want to complete the trade when this user, with zero reviews, didn't wanted to send the keys first.
So, no trade was made, they thanked me for my time and effort and we wished each other a good evening. Then I removed this user from my Steam friends list and later found out, that I got a negative review here as revenge.
NEVER do trades or business with this user, it will only cause you problems.
Link to all of our communication:
https://postimg.cc/gallery/bJbffyZ
https://imgur.com/a/oNYZEVq