She and I are 'bound' (together) by our shared past. [=we are connected to each other because we have the same past]
The captive was 'bound and gagged'. [=tied up and stopped from talking with something that covers the mouth]
I felt 'honor bound' to defend them. [=I felt that I had to defend them because it was morally right]
(..) Of course I'm afraid for her! It just seems very dangerous. She'll be protected the entire way. The Faith Militant are very stern with those who overstep their bounds. And Queen Margaery isn't your mother. I suspect the gods will predispose the common people to gentleness on her behalf. (..)2016 TvShow: Game of Thrones Title: Blood of My Blood Season: 6 Episode 6