The heavy responsibility was hard to take on, but he accepted it anyway.
Tips
usage
难当 splits into two meanings depending on what 当 means here: (1) 'hard to endure' for sensations like heat, itch, embarrassment - 酷暑难当, 痒得难当; (2) 'hard to assume' for roles or duties - 重任难当, 大任难当.
