"深信不疑“怎么翻译？

believe it without doubt

英语必须放在例句中分析：
I trust him without any hesitation.我对他深信不疑。

这样译较好：
be deeply convinced.
firmly believe.

Believe undoubtingly
或者说:
Believe in firmly

trustfully 一个副词搞定

be deeply convinced.
firmly believe. 这种译法最地道