First term (2016–2019) In the 2016 local elections, Guianiwas elected vice mayor of Cotabato City. Her brother, Japal Guiani Jr., was re-elected as mayor for a third term but he died a few months later on September 22, 2016 due to cardiac arrest. His sister took over as mayor as per local government succession rules and took oath the following day. She would serve the remaining term of herbrother. Guiani would continue the policies of her brother while adding modifications. She aimed to improve the standards of living in her city. She was mayor of Cotabato City when the
early 2019 two-round plebiscite which seek to establish the
Bangsamoro autonomous region to be led by the
Moro Islamic Liberation Front (MILF). Guiani campaigned against the inclusion of Cotabato City in the then proposed region but voters favored both the establishment of the new region and the inclusion of the city to it. After the results became known, she publicly expressed intention to file a formal protest to the Commission on Elections.
Second term (2019–2022) Guani would run in the 2019 elections for mayor. Her bid was successful becoming the first ever woman to be elected as Cotabato City mayor. She vowed to continue her policy against crime, particularly her ronda program. The ceremonial turnover of the city to the Bangsamoro regional government would take place on December 20, 2020, which she did not attend. She also opposed the extension of the
transition period to 2025, when it was still a proposal. She would take part in the 2022 elections to secure a second regular term. She filed a disqualification case against her political rival Mohammad Ali Matabalao alleging his campaign of engaging in vote buying Guani would lose to Matabalao. She filed the case before the Commission on Election
en banc but withdrew it and instead filed it with the Second Division which dismissed it for lack of
jurisdiction. The city council under Matabalao's administration formally affirmed the 2019 plebiscite which led to Cotabato City's inclusion to the Bangsamoro. ==Personal life==