I am following the book German for Reading: A Programmed Approach and on page 207 point 39 there is an example sentence:
... und mit Unbefangenheit die Zügel der Regierung in die Hand nahmen ...
which translates to
... and took the reins of the government into their hands with ease ...
and actually the author specifically says that Unbefangenheit = ease.
However, when looking upon a dictionary, I can only find meanings like impartiality, objectiveness, unbiased, etc. There are nothing relevent to ease. In fact, I even found a paper saying that
"Unbefangenheit" is the German translation of the Japanese term mushi ... (which) is an expression of "non-ego"... The German translation ... (means) "dissolution of bias/prejudice/interest", it indicates something like "free of ego", "impartiality" or "absence of subjectivity".
Thus my question is, how is "Unbefangenheit" related to "ease"? Is it some ancient deprecated usage?