I am a 60 year old American. If I was a couple of years older, I would very likely have fought in the war in Vietnam that began following the French withdrawal in the 1950s and continued to 1975. The war was a tragic event in my country, but MUCH more tragic for the Vietnamese people. Americans of my age and older remember the war very well, but after so many years, I think I can say we do not have any negative opinions of the country. On the contrary, the passage of time, and the realization that the war was a terrible mistake, has caused Americans, in general, to have warm feelings toward the Vietnamese people. Those people were victims first of the colonial French empire, then the despotic Diem regime, then the North Vietnamese Communist insurgency, then the US intervention, and finally the post-war oppression against those who supported the South Vietnamese government. Since the war, many aging Americans who fought there have returned to the country, some to heal the wounds in their hearts and in the hearts of their former enemies; some to find their own children they fathered back then, and some even to live the rest of their lives in a beautiful country!
So Trân Thi Thanh Thúy, in summary, I have nothing bad to say about Vietnam or the Vietnamese people. I wish you all the very best.
About Vietnam: the food is awesome, people are friendly and they had a war in the 60s that lasted more than ten years and killed more than half of its population. They have a tropical forest just like here. There is a lot of prostitution and poor women have no choice but selling their bodies to make money. Their currency is very devalued and they are the only country in the world that have a 500 thousand bill (dong). Most of the Vietnam is rural and they look "Asian" more like Chinese and Japanese people and less like Indonesians and Filipinos who are brown.
About Vietnamese: it's the only official language of Vietnam and the mother tongue of more than 80% of its residents making it the most ethnic homogenous country in Southeast Asia (not like Indonesia and the Philippines that have hundreds of languages). It's written in Latin script unlike Thai and Khmer because of French colonization. It's a tonal language and they have six or seven different tones that to my ears sound exactly the same. The grammar is simple. It sounds a lot like Chinese, I couldn't distinguish them if I hear it