High Court judge Jessie Lesiit ruled that Ruth Kamande, 25, killed Farid Mohammed in cold blood after stabbing him 22 times following a domestic dispute.
Kamande has been in custody since 2015 when she was arrested. She will be sentenced on July 11.
Last year, she sat the Kenya Certificate of Secondary Education examination at the prison and scored an A-. She is now a trained paralegal.
Lesiit ruled that her actions proved that she had malice when she killed her boyfriend.
She said the prosecution had proven beyond all reasonable doubt that Kamande committed murder.
"It is clear from the prosecution's evidence that the stabbing was not done at a go. It was done at intervals," Lesiit said.
Kamande said she stabbed Mohammed in self defence. However, a key witness who was present when she killed him discredited her claims.
The witness told the court he heard Mohammed screaming for help. He went near a window, but Kamande followed him and stabbed him again, he said.
Justice Lesiit said the rape allegations made by Kamande were false. The doctor's report showed she had not been raped, the judge said.
nelson masaya...that thigh though...
Charming...manzee... hi kitu itafungwa to bure
phreeman bakari ...si ameuwaa wengii sana sema ni mmoja ndio sisi twajuwa
kiri...she can come kill me as well...
KENYAN NOISE ....Stab me too Kamande,Stab me...Uuurgh!!!
Being Charlie ...Sly Queen Ruth Kamande and her irk will be endbof Kenya