Christine Archibald – the first person killed in the London terror attacks to be identified – died in her fiance's arms, according to a report.
Ms Archibald, from Castlegar in British Columbia, was engaged to be married to Tyler Ferguson, his sister Cassie Ferguson told Canada's CBC News.
Ms Ferguson said her brother was "broken in a million pieces".
"He held her and watched her die in his arms," she added.
In a statement, her family said they were grieving the loss of their "beautiful, loving daughter and sister".
"She had room in her heart for everyone and believed strongly that every person was to be valued and respected," they said.
"She lived this belief working in a shelter for the homeless until she moved to Europe to be with her fiancé. She would have had no understanding of the callous cruelty that caused her death.
"Please honour her by making your community a better place. Volunteer your time and labour or donate to a homeless shelter. Tell them Chrissy sent you."
Ms Archibald is the first person killed in the attack to be identified.
Canadian Prime Minister Justin Trudeau said he was "heartbroken" that a Canadian was among those killed.
In a statement on Sunday, Mr Trudeau said: "Canada strongly condemns the senseless attack that took place last night in London, United Kingdom, which killed and injured many innocent people.
"I am heartbroken that a Canadian is among those killed."
Seven people were killed and dozens 48 injured on Saturday night after a van drove into pedestrians on London Bridge before three men got out and began stabbing passersby.