なのも

[zuotengdazuo]

富美さんを困惑させるだけなのも、僕には分かっている。

Hi. What is the function of the も here?
Thank you.

 

[bentenmusume]

The typical "also, in addition" meaning of も.

If it were は, the speaker would be saying that he understands this, at least (and maybe nothing else). With も, he's saying that he understands this, too (in addition to other factors that might be at play).

 

[zuotengdazuo]

Thank you. I get it.