Betsa graduated from Taras Shevchenko National University of Kyiv in 1999.

In 2001-2005 and 2009-2012 Mariana worked at diplomatic positions in the Contracting-Law Department of the Ministry of Foreign Affairs of Ukraine.

Betsa worked twice abroad: from 2005 to 2009 - at the Embassy of Ukraine in the Kingdom of the Netherlands, and from 2012 to June 2015 - at the Permanent Mission of Ukraine to the international organizations in Vienna (OSCE issue).

During her time at the Foreign Ministry, she was trained at the University of Westminster, the Clingendhal Institute of International Relations (The Hague, Netherlands) and the Ministry of Foreign Affairs of the Republic of Indonesia.

Mariana is a specialist on international law, human rights and the OSCE.