Hermans made her professional debut on 23 January 2016, scoring a six-round unanimous decision (UD) victory against Galina Gyumliyska at the Sportloods Waarborre in Asse, Belgium.
[7] After two UD victories in non-title fights, Hermans moved down a weight class to challenge Claressa Shields for the unified WBA, WBC, and IBF female middleweight titles on 8 December 2018, at the StubHub Center in Carson, California.
[9] Following a TKO victory in a rematch with Borislava Goranova in October 2020,[10] Hermans faced Luiza Davydova for the inaugural European female middleweight title on 5 December 2020, at the Fight Off Training Center in Wavre, Belgium.
[12] Switching to super-welterweight, she claimed the vacant IBO title with a win over the previously unbeaten Mary Spencer by unanimous decision in Shawnigan, Quebec, Canada, on 16 December 2022.
[13] Hermans made an emphatic first defense of her title on 17 June 2023 when her challenger, Maria Lindberg, retired at the end of the first-round of their fight in Roosdaal, Belgium, having been knocked to the canvas just before the bell.