It would be impossible to impose the decision as it's a democratic country with certain requirements of law and Constitution.
I have good hopes for the referendum. Only a minority of the population is pro-Russian. The vast majority apreciate the relation with the EU and a good half already hold dual citizenship with Romania and are in fact EU citizens.
The objections in some of the regions are more nuanced. For example Gagauzia was populated by people without historic ties to Romania and they fear that if Moldova were to unite with Romania their autonomy would be abolished. They should have no objection to becoming EU members as part of Moldova; but such fears must be addressed. The Moldovan government has started a process of cultural openness to this effect.