chéngshuāngchéngduì
ㄔㄥˊ ㄕㄨㄤ ㄔㄥˊ ㄉㄨㄟˋ
Simplified 成双成对
Taivo → Settings → Partner inbox → Make the link. It stays in this browser.
Keep 成雙成對 and it comes back until you know it.