York Regional police say they were called to a home in Aurora, just after 8 p.m.
When they arrived they found a 32-year-old woman "in grave condition." She had trauma to the head and was not responsive, police said.
The woman was transported to hospital where she has undergone surgery.
Police took Mohammed Mahdi into custody and later charged him with attempted murder.
During a court appearance in Newmarket on Saturday afternoon the victim was identified as Manisha Yalahy.
Mahdi was ordered not to be in contact with a large group of people — many of whom also have the surname Mahdi — as well as the victim.
Prosecutors asked for a three-day adjournment, which was granted.
Mahdi will remain in jail until his next court appearance on April 16.