Not all hack/scam messages are like this, but the majority of them have poor spelling and grammar and that should be a HUGE clue. Just like with spam. Don't trust messages with misplaced apostrophes!
I refused to trade with someone recently because I was suspicious. Occasionally if I'm feeling generous I may agree to a price haggle on one of my store items but this guy first offered me one price, then said wait, can I trade you an item worth the same amount instead, then after I told him no he still sent me a trade with an even lower amount of gold than he offered me the first time. Too many inconsistencies and too many scammers and hackers out there to worry about hurting one person's feelings; I denied him and thankfully he went away.