People wishing to remain modest is not a display of sissiness.
From the orlandosentinel.com
His sissiness was completely un-canceled-out.
From the hecklerspray.com
That name still makes people sound like goody-goodies, but you have proved there's no sissiness about the guts that these people have and the good work that they do.
From the time.com
More examples
Effeminacy: the trait of being effeminate (derogatory of a man); "the students associated science with masculinity and arts with effeminacy"; "Spartans accused Athenians of effeminateness"; "he was shocked by the softness of the atmosphere surrounding the young prince, arising from the ...