Jessen was an Enaran female who grew quite fond of Harry Kim during her time aboard the USS Voyager 1n 2373. The feeling was mutual, and the two of them spent practically the entire trip to Enara Prime together. She was an engineer and worked closely with Torres.
When B'Elanna Torres revealed the memories she had received from Jora Mirell, Jessen was hesitant to believe B'Elanna. She would volunteer to have Torres telepathically link with her to view the visions Torres had. (VOY: "Remember")
Jessen was played by Athena Massey. It is unclear what happened to Jessen's relationship with Harry, as the episode focused on B'Elanna's experiences and the Regressives. No mention was made of Jessen in later episodes so one can assume they went their separate ways.