The only way to be absolutely sure you are trading with the actual DMarket account is to compare the bot’s registration date (it is shown on Steam in the Trade Offer window). The date is the only parameter that cannot be fabricated by the bot.
For example, the initial trade was offered by DMarket Bot #1234. The scambot will change the name and even profile avatar to match the actual account, so the profiles will look almost identical. Only the date will differ, so please pay extra attention when accepting the trade (Fig. 1)
FIGURE 1
Pay attention to trade contents and recipient: it's crucial to use the Steam Mobile app for 2FA verification. Scrutinize trade details and heed Steam's warnings (Fig.2), especially regarding recent username changes or voided trades. Steam provides prominent yellow warnings for such actions; take them seriously and avoid authorizing trades with these cautionary notes.
FIGURE 2
BUTTON BLOCK