disloyalty

a. 不忠
n. 不忠实

He was/felt deeply wounded by their disloyalty.

因为他们不忠, 他十分伤心.

I know he suspect me of disloyalty, but I suppose I'll just have to brave it out.

我知道他怀疑我不忠，但是我想我不得不硬着头皮去见他。