The Langston twins found their half-sister Nicky Sikora through the television program Missing Pieces in 2012.
Ms Sikora read Sophie's eulogy.
Mr Thomas spoke of Sophie's outlook on life, and urged the people gathered to live their lives the way Sophie lived hers.
He said Sophie liked to keep busy, make others happy, she "never missed an opportunity to make other people smile" and loved animals.
While Mr Thomas was a corporate man, Sophie was "a bit of a hippy".
The couple met when they were 15-years-old and Sophie was a student at St Cuthbert's College.
"We filled a lot of gaps in each other," he said.
The couple had a dog together who was in the church for the funeral.
Mr Thomas said the twins could communicate with each other without speaking, and he swore to look after Laura for the rest of his life.
Laura didn't give a eulogy to her sister, saying simply "I love you, Sophie."
Flowers from Eastridge Flowers where Sophie had worked as a florist since 2007 adorned the church.
Friends and family were encouraged to be brave like Laura and Sophie were and get in front of a portable camera set up to record messages for Laura and Mr Thomas to reflect on.
More than $34,000 had been raised to pay for the funeral on Givealittle.
Sophie and Mr Thomas were returning to Auckland after attending a family funeral in Whanganui on June 30 when the crash happened.
