He was filled with remorse for not believing her.

他因为没有相信她而懊悔不已。

《牛津词典》

She shuddered to believe, yet could not help believing, that it gave her a sympathetic knowledge of the hidden sin in other hearts.

她战战兢兢又不由得不去相信，那字母让她感应到别人内心中隐藏着的罪孽。

youdao

That I was desirous of believing her indifferent is certain, — but I will venture to say that my investigations and decisions are not usually influenced by my hopes or fears.

我当初确实希望她无动于中，可是我敢说，我虽然主观上有我的希望，有我的顾虑，可是我的观察和我的推断并不会受到主观上的影响。

youdao

The tribunal heard the girl visited the school nurse and said she had had a sexual encounter, but the school did not contact her parents, believing she had consented to the encounter.

BBC: Stanbridge Earls School

They would be happy to see her not only take over the party but also contest the 2012 presidential election, believing that she lacks the stature to challenge Mr Sarkozy.

ECONOMIST: France's Socialist Party