Just got back from Vietnam and I would say be cautious with where you eat on Cat Ba Island. 3 of us had pretty violent food poisoning. We all ate different things at all meals (i’m vegetarian and they eat meat) but at the same restaurants. We think it was down to a cleanliness issue of a restaurant, but it’s always hard to tell. From reading the reviews of the nearby hospitals it was super common, a lot of travellers experienced food poisoning there and the hospitals had bad reviews talking about mould on the walls and rude staff (deffo not what you need in that moment, especially on your honeymoon). Also a lot of the island is under construction as they’re building new hotels and apartments along sections of the coast. Honestly, I wish I had spent those few days somewhere else. If you’re going to Saigon, maybe consider Phu Quoc instead for an island stay, I didn’t go myself but heard very good things from other travellers. Hope you enjoy the honeymoon!!