This is the 18th most frequent Vietnamese word.
rất
"Rất" means "very" in English.
The word 'rất' emphasizes the intensity of liking something in this context.
Tôi rất thích món ăn Việt Nam.
I really like Vietnamese food.
The word 'rất' here modifies the adjective to indicate a high degree of the quality.
Thời tiết hôm nay rất đẹp.
The weather is very nice today.
In this sentence, 'rất' is used to intensify the expression of the emotion 'happy'.