Yes, there are multiple flights from Vietnam to Reykjavik for under 29,967,728₫. The cheapest flight booked recently is on British Airways for just 29,575,842₫, but on average you can expect to pay 34,762,564₫.
There are no direct flights from Vietnam to Reykjavik, but Cheapflights can provide you with all the information you need to find the fastest route with the fewest stops.
Singapore Airlines and British Airways can get you from Vietnam to Reykjavik in just under 28h 10m. Your travel time can differ by up to 1h 30m. Both multi-stop and direct flights can be found to your destination and back.
Flying on British Airways is currently your cheapest option to Reykjavik, with prices starting at 29,575,842₫. Another option worth looking into is Singapore Airlines, starting at 37,367,452₫ round trip.