Translation:I had to hustle to buy this book.
Then the English translation is wrong. The English means, "I had to hurry to buy this book." The word "hustle" has several meanings, e. g., "move quickly" or "push the sale of something (possibly sex)," but it doesn't mean "to push through a jostling crowd" which seems to be the meaning of "chen chúc."
"Jostle" is better but it refers to the shaking, pushing or crowding that moves or disturbs someone. It doesn't have to happen in a crowd.
I can't think of a single word for "chen chúc" in English. I would use a phrase with the word "crowd" and some verb, e. g., "push through a crowd" or "work through a crowd" or "make my way through a crowd." There may be a good one word translation but I can't come up with one.
I think the main problem is moreso the ambiguity in the word, as it has two meanings which could both potentially be the correct translation: as in 'move quickly in a rushed or crowded setting', or 'bargain or haggle'. But thankfully it's made clear above, the vietnamese word has the first meaning
I wouldn't say hustle has a connotation of a crowded place. More of moving fast/working hard/struggle to achieve the goal. So in my view, chen chúc does not correspond to either meaning of hustle.
I.e. yes, one struggles when hustling, and one struggles through a crowded space. But the English focuses on the effort, regardless of crowd, while the Vietnamese word refers specifically to the act of going into a crowded space.
I've been trying to think of a good word, but I think this is probably a case where English just doesn't have a specific word that conveys the meaning. We can say things like "elbow through, elbow in, squeeze through", but people would have to know already that it was crowded, or we'd put it in the same sentence: I had to fight through the crowded store to buy this book. I had to elbow through the crowd to get to the door.
So it is a good word for us to learn, but in a program like Duolingo, where it focuses on direct translation, it's tough to come up with a good equivalent.
"Hustle" in the sense of "hurry" doesn't imply a particular setting. One can "hustle down the street (or to the bookstore)" all alone. There is no necessary sense of a crowd. One could have to "hustle" to get to the shop before closing time. It doesn't mean "to push through a crowd." In this part of the world at least, it just means "hurry."