I'm a Rogue assassin, can I equip two identical daggers in both hands?

Hello friends... I need help to one question...

I'm interested in buying 2 daggers for my rogue, two "Wrathful Gladiator's Spike"...
Can I equip two identical daggers in both hands?

If they aren't unique or unique-equipped, the answer is yes.

What do you mean unique item? If I buy 2 identical ones, can I equip them?

You can, if that item is not
"Unique" - you can have only 1, doesn't matter if it's in bank, equipped or otherwise, example https://wotlk.cavernoftime.com/item=50671
"Unique-Equipped" - you can equip 1, but you can have any amount in bags/bank
Also make sure it's "One-Handed", instead of "Main Hand" or "Off-Hand", as some PVP items have this tag on them.