You may find nice Ukrainian woman who will be eager to marry you, her American man of a dream everywhere. If you want to find her in US, try to visit Chicago Ukrainian village or Brighton beach in New York, but be aware to find there Ukrainian but not Russian woman.
If you want to find Ukrainian woman in Ukraine and then to marry her, try to find her in big Ukrainian city like Kyiv, the capital of Ukraine or on west of Ukraine like Lviv, Ternopil or Rivne.
Of course, according to destabilization on the East of Ukraine, do not visit Donetsk or Luhansk region in search of Ukrainian girl. Maybe they are very eager to live that part of the country as quick as possible, but for sure not because of love and feelings to you, but of political situation on East of Ukraine. Read also: Why Ukrainian brides are popular among foreigners?
By the way, girls from western Ukraine are usually more moral, share traditions and are more intelligent. Of course, this is subjective opinion, though; it has the right for life. Read slso: Why are Ukrainian women so sexy?