Lots of people offering Lot's of things but whom to believe and how
For sure most likely someone with a lot of positive feedback about a transaction is the one that you could trust just basing on his feedback, you should still be careful making transactions to someone else.
Look for someone trusted here in the forum that could do escrow here are some recommended bitcointalk escrow.
You can find some escrows here. https://bitcointalksearch.org/topic/recommended-bitcointalk-escrow-services-2439910
If you're not talking about the members here in the forum or just random people online theirs no way you could know.