Marry Me!
Complete a poster in the Wanted List "Bride's Training" in WANTED Versus (Secret)
To obtain this achievement you need to unlock WANTED Versus mode. You will obtain WANTED Versus by unlocking all modes which can be done by completing up to the sixth chapter on Episode Luffy in the Paramount War mode.
To get this achievement you need to complete at least one of the wanted posters in "Bride's Training". These wanted posters are fights where you can build your own team to fight against the computer. Bride's Training has a one star difficulty.