Bessarabia was delineated in the Soviet sphere of interest in the Molotov-Ribbentrop pact, yet naturally Romania was not part of this treaty.
As I understand it the Romanian government (and the Soviet Union) were ready to go to war over the issue except that the German and Italian governments persuaded the Romanian government to accede to demands. This is something I dont quite understand as:
Why then did both the Axis powers and the Romanian government accept Soviet terms?
Romania was not on good terms with Bulgaria and Hungary and risked being attacked from 3 direction. It would soon lose territory to these two, backed by the Axis (with which Romania was not on good terms at the time, this would change with the abdication of Carol II).
Check out the record of Hitler made by the Fins (without his knowledge), he talks about the situation on the Eastern front and how in 1940 he feared that his campaign could have ended before it even started if the Soviets would have invade Romania and taken over the Ploiești oilfields.
The king held two Crown Councils, the prevailing opinion was that the army would not be able to hold off the USSR without significant support from a Western army (which was not possible). See what Carol wrote in his journal (in Romanian but automatic translation should be good enough): https://adevarul.ro/locale/targu-jiu/carol-ii-lea-despre-cedarea-basarabiei-romanii-n-au-cea-mai-mica-doza-orgoliu-national-clipe-intr-adevar-grele-1_5aec7773df52022f7594062a/index.html
The [Crown] Council is taking place, and I came out of it bitter and disgusted. All those who made the heroes at lunch deflated. Only 6 votes out of the 26 present were for resistance. Their names deserve to be inscribed in golden letters in the book of Romanian dignity: Nicolae Iorga, Victor Iamandi, Silviu Dragomir, Traian Pop, Ştefan Ciobanu, Ernest Urdăreanu. All the others, with some nuances, they were for accepting the ultimatum. (...)
Longer discussions were useless. So I ended the Council with a short speech, in which I said that it was the most painful day of my life, this day when I had to rejoice that my son had passed his baccalaureate. I think it is a great mistake to give up almost a quarter of the country without any resistance, but I am overwhelmed by the opinion of the vast majority of those to whom I have sought advice. I left without shaking hands with anyone, deeply bitter and convinced that the consequences of those decided will be very bad for the country, even if, as Argetoianu thinks, very soon we will regain what we lost.
On the Axis position:
Saturday, June 29
Today or maybe yesterday, the Axis advised Hungary and Bulgaria not to move. Too late. They seem satisfied that I gave up. Of course, it was in her interest and complicity
Finally, an interesting perspective on the cost of combat aircraft:
A small comic-tragic incident - the king writes in his diary - was during Iorga's attack on Țenescu and Slăvescu; I asked him how much he thought a bomber would cost, he replied that he thought it was probably about 500,000 lei; he was extremely amazed when he heard that it was 30 million!