Other than being a claim by a man who just conquered a province of Ukraine that he has no more territorial objectives, we have a reason to be very suspect of this so-called reassurance:
Putin tried to reassure Ukrainians that Moscow did not seek any further division of their country. Fears have been expressed in Kiev that Russia might move on the Russian-speaking eastern parts of Ukraine, where there has been tension between some Russian speakers and the new authorities.
"Don't believe those who try to frighten you with Russia and who scream that other regions will follow after Crimea," Putin said. "We do not want a partition of Ukraine."
If I might point out the obvious, this is in no way a comforting statement. If Putin wants all of Ukraine, the absorption of the entire country into Russia is not actually a partition of Ukraine.
Just saying.
But no worries. Our crack foreign policy team is right on this. This will be just great.