Lee Hyeongwon, 32, received the death sentence for murder, a jail term of 14 years for robbery and a two-year prison term for theft. He was also ordered to pay VND700 million ($30,700) to the victim's family.
The prosecution called for the strictest punishment, saying Lee had shown "villainous signs and tried to kill more than two people" when committing his crime.
The defendant told the court that he had come to work in Vietnam on different occasions.
In December 20, 2019, while working at a karaoke parlor in District 5, Lee went to Phu My Hung, a residential area in District 7 that is home to the biggest South Korean community in HCMC, to spread leaflets advertising the parlor.
As he took a break at a park nearby, Lee came up with the idea of breaking into a house in the area and robbing its inhabitants, the prosecution said.
He chose the house of Yoon Sang Yong and his wife Jung Young Sook, both South Koreans, to commit the robbery.
He returned to the house that night wearing a raincoat to avoid being recognized via security camera footage.
He climbed into the house where Yoon and Jung lived with their two children from the window on the first floor.
Around midnight when everybody in the house had gone to bed, he went into the kitchen on the fourth floor and got a pair of gloves and a knife.
When Jung discovered Lee and called out for help, he stabbed her in the neck and stabbed the husband several times when Yooh rushed to try and save his wife.
Their oldest child, a 16-year-old girl, also got stabbed as she tried to reach her parents from another room.
Lee then kept the girl hostage and demanded that Yoon open their safe, but for some reason, it could not be opened.
Yoon begged Lee to spare his family, giving the latter a branded leather bag with VND5 million in cash, four smartphones, the house key and a car key.
After taking everything Yoon gave him, Lee took the girl to the room of the youngest child to get another smartphone and got out of the house and drove away in the Yoon’s car.
In Binh Thanh District, he threw five smartphones into the Saigon River before driving to a vacant land plot in Thu Duc City. He burned the car there.
After returning to the apartment he rented with another South Korean, he stole $2,000 from his roommate and fled.
He was arrested four days later, hiding in District 1’s backpacker area.
Jung succumbed to her neck injury later.
Lee said at the court that he was "genuinely" sorry for his act and apologized to the victim’s family.