They 'swore' (an oath of) allegiance to the United States of America. [=they formally promised that they would be loyal to the United States of America]
He 'swore us to secrecy/silence'. [=he made us promise not to tell anyone his secret]
He was so disgusted by the election results that he 'swore off' politics for good.
(..) from "Winterhell"? No, ain't seen anyone like that. I heard they was all traitors. Don't need no traitors in here. I swore to her I'd bring her daughters home. Sure I can't get you a bit more kidney pie? What? It's nothing, my lady. You wouldn't be screwing your face up like that if it was nothing. (..)2014 TvShow: Game of Thrones Title: Mockingbird Season: 4 Episode 7
(..) You've ordered us to be night watchmen. And as for women, there are thousands in Meereen you can pursue. There is only one, and she does not want me. You swore me your sword. My sword is yours till the day I die. So if I command you to stay in Meereen and patrol the streets? I'll stay in Meereen (..)2014 TvShow: Game of Thrones Title: Mockingbird Season: 4 Episode 7