Here are 2 ideas i got that could really make keeping track in trading easy
1- Previous Owners
You would be able to see who owned these items before you in order
Here's how it would go
click the 3 dots on the top left of an item
Or
Click a button that shows you your inventory but in the style of the index and click on the item you want
(if multiple of them then be able to choose which one exactly from 1 to 99 (the max items i think))
2- Trading History
You would be able to see in the trading tab next to the index button , another button called Trading History
When clicking on the button it would do the same thing as the "select a player to trade with" menu but instead it would show every trades you did with THESE informations
- the player you traded with
- the offer he did
- the offer you did
- if the trade was successful or denied
Extra
You should also be able to remove trades from history with a good old X button and a "are you sure ?" Pop up . Then it will put a "this trade has been removed" or something like that