So, according to your logic, Romania was never existent and we have to return Wallahia, Transylvania and Moldavia to Hungary. Or, maybe, we have to resurrect the Golden Horde and return these lands to them, because it was their land in 1200s.
Also, there is a very large Hungarian minority in Romania who wants to merge with Hungary.
This is not the first time that I am seeing frustrated Romanians posting here, asking Moldovia to merge with Romania. But the truth is that not even 10% of the Moldvins want to do so (I mean the ethnic Moldvins, who constitute 69% of the population). Support among the other minorities (Russians, Gagauzes, Ukrainians, Bulgars.etc) for this measure is practically 0.
And remember that some 600,000 Moldvins work in RF (15% of the total population, one-fourth of all adults). The attachment to Russia is much more than any historical link to Romania.