I'm Vietnamese and I can answer your question based on what I know about the Vietnamese. Most Vietnamese think that China wants to invade Vietnam and make it a part of China. At school, Vietnamese children are taught about the many Chinese invasions of Vietnam and parents tell their children that China has always wanted to invade Vietnam but still hasn't found the right time. It doesn't help that recently there are disputes between China and Vietnam in the South China Sea. Most Vietnamese think that China is getting more powerful now and will invade Vietnam soon. It is a totally illogical fear I know, since the world has changed and clearly most Chinese people nowadays do not have imperialistic ambitions in taking over neighbouring countries and are just content that their economy is going well and that China is becoming more prosperous. In today's world, land expansion is no longer feasible and profitable, but still the anti-China sentiment has became a deep part of our culture. Our history is shaped by being independent and winning our independence from China. Most of our heroes are those who resisted against Chinese invasions. Today if you go to Vietnam, most of the important roads are named after these people.
Still there is a very love hate relationship, because as much as the Vietnamese hate China, they also really love Chinese culture and history. Chinese civilization is admired and Chinese cultural elements are readily welcomed and embraced. I would say Vietnamese culture is very strongly influenced by China, this is seen on all aspects of traditional Vietnamese culture from celebrations to traditional clothes and music. Chinese loan words in Vietnamese are considered more elegant and poetic than the native words and Vietnamese have adopted many idioms that are translated literally from Chinese (even approximating pronunciation). Chinese poetry is also very appreciated especially on New Year day.New temples being constructed still have signs written in Chinese characters even when most of the population can't read them. So you can see, it is a very strange relationship. Hopefully since the world is becoming more globalised, more Vietnamese people will be using sites such as Quora so that we can clear this misunderstanding. It's better to make friends than enemies :)