The woman confessed to killing the man by cutting his chest and removing his heart. (Representational Image)

Dhaka: A young woman who cut her lover's heart out and slashed his throat has been sentenced to death by a Bangladeshi court, a prosecutor said Tuesday.

Fatema Akhter Sonali, 21, acted out of revenge after the man refused to marry her and secretly kept recordings of the couple having sex, prosecutor Quazi Shabbir Ahmed said.

She had also found video footage of him having sex with other women on his laptop, Ahmed said.

"It's rare for a woman to be sentenced to death. But her case was exceptional," he told AFP.

"She admitted to the court she killed her lover, Emdadul Haq Shipon, for refusing to marry her and for keeping a recording video of their sexual intercourse in his laptop."

The judge delivered Sonali's sentence on Monday in a packed court in the southwestern city of Khulna.

In her confession, Sonali said she spiked a soft drink with 20 sleeping pills and gave it to Shipon, a 28-year-old part-time lift attendant at a hospital.

When he fell unconscious, she bound his hands and feet before killing him by slitting his throat.

Sonali then cut open his chest and removed his heart.

"She told the court that she was curious to see how big his heart was. She said a man must have a big heart to carry out such audacious crimes," said Ahmed, using a Bengali idiom.

Sonali committed the murder in March 2014 and can challenge the sentence in a higher court.

If her execution goes ahead she will be the first woman to be hanged in Bangladesh, according to Tipu Sultan, a deputy inspector general of prisons.