Sometimes it happens at the train station, sometimes on the street. Sophie English can see the question in their eyes, before they ask it.

"Excuse me, do you mind if I ask where you come from?"

Some strangers think she is Chinese, Maori or even native American. The truth is, Sophie English was born in Saigon during the Vietnam war and adopted by an Australian family.

"I am Australian as they come, you know? Frickin' I like Vegemite, meat pies and I can swear like a trooper.

"I feel totally privileged to be Australian. I don't feel anything else but Australian, but ... there's still that part of me that is Vietnamese."

Sophie is returning to Vietnam to make peace with her past, as the nation commemorates 40 years since the end of the war.

She was only 10 months old when she was flown out to Australia in 1969.

"I've lost my whole culture. I have lost my whole identity, my language, my food. You know, I'm 46 years of age, Vietnam back then would have been completely different to now."

Sorry, this video has expired Sophie talks to a Vietnamese mother about adoption

Sophie has very little information about her biological family or why she was adopted. Like so many others who were sent out of Vietnam during the chaos, the paperwork was either lost or has turned out to be wrong.

As she walks the streets of Ho Chi Minh City, she could be walking past her mother at anytime and not know it.

She is torn between maintaining hope and trying to extinguish it, so she can get on with her life.

"I have just felt heartbroken a lot of times. It is so been so confronting and just mentally and emotionally draining," she said.

Hundreds adopted from Vietnam during war

Hundreds of Vietnamese children were adopted by Australian families during the Vietnam war.

Supporters of the program argued that the children would have a much better life in Australia, rather than living through the tail end of the war in their country of birth.

It's a dilemma that still haunts Sophie English today. Would she have been better off to stay with her family in Vietnam, even if that meant a life of poverty?

"If there hadn't been a war, if I hadn't been adopted, if I had stayed with my birth mother, that would've been me. I mean I might've been on the boats, fishing and I would be working really hard like them, but I would have that sense of family," she said.

"I would probably have grandchildren by now, and I would have that deep need in me fulfilled."

The reality of life in Vietnam is harsh. The average daily income is little more than $5 a day. It is very different to Sophie's middle class life in suburban Sydney.

But, she sees something different in Vietnam, a sense of resilience and calm, despite the years of war.

"All these people and it's a calmness out there, they're all calm," she said.

"That real sense of calm that Westerners are trying to achieve through fricking yoga and Buddhism and pilates and all this crap stuff, they've already got it with less than we have ... I absolutely love that.

"Their strength of spirit. Their diligence and their family but really their determination and their real strength of spirit ... they have got such fortitude on the face of adversity and they still smile and they work their bloody hearts out."

Adoptive parents need to be better educated about trauma

Sophie holds little hope of ever finding her mother in Vietnam, and is estranged from her adoptive family, so making a connection with her motherland is a lifeline.

Forty-six years after she was adopted, she is still searching for identity and feeling the traumatic effects of being separated from her biological family.

Sophie wants adoptive parents to be better educated about the lifelong trauma of children who are taken away from their families and their homeland.

"Parents who are going to adopt a child from another culture or just Vietnam need to love that child. Do not adopt a child if you are not going to treat it right and you are not going to understand that it is a work in progress," she said.

"An adopted child is not a clean slate, whether they're one or five, they are coming to you from a different culture that needs to be addressed."

Watch Foreign Correspondent's Vietnam - Are You My Mother? on ABC tonight at 8:00pm.