Joan Lawrence spoke ahead of a service at York Minister on Monday to remember the University of York chef, who was 35 years old at the time she vanished.
She said: "I think we will get an answer. I pray every day that I will get one.
"When it was her birthday, I would think back to when she was born. There's no card to send, now. There's no present to buy. One thing that's very, very difficult is that there's no grave to visit."
Friends of Claudia are due to light ten candles in her memory inside the Lady Chapel of York Minister on Monday afternoon.
She was last seen on 18th March 2009. No body has ever been found but police launched a suspected murder investigation.
At first, officers focused their attention on the route between Miss Lawrence's home on Heworth Road and her workplace.
Nine people have been arrested or interviewed under caution in connection with the disappearance. Files were submitted by officers to the Crown Prosecution Service but there was insufficient evidence to bring charges.
Hundreds of officers were initially drafted in to help with the investigation. The probe has since been scaled back.
North Yorkshire Police has warned that the withholding of vital information could be hampering their efforts.
Today marks the 10th anniversary of Claudia Lawrence disappearance. Join me in praying that someone will come forward with news of Claudia, for hope & comfort for her family & friends.— John Sentamu (@JohnSentamu) March 18, 2019
Detective Superintendent Dai Malyn said: "It remains the case that we strongly suspect key and vital information is being withheld that could provide the breakthrough that we all want to see, not least Claudia's heartbroken family.
"Unless we get information or intelligence to suggest that Claudia came to harm as a result of an opportunity taken by someone unconnected to her, me and the team still strongly believe the answer lies locally.
"As with some recent cold case successes, the breakthrough has come from the public and we still have confidence that this will be the case."
In 2014, Premier reported how the 2,000th day since Claudia's disappearance was remembered by the Archbishop of York.
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