What does Yaffa mean?
From Hebrew יָפֶה/יָפָה (yafeh/yafah) 'beautiful, lovely'. Yaffa (also Yafit) is a modern Hebrew beauty name; the same root names the city Jaffa ('the beautiful').
What does Naava mean?
From Hebrew נָאוָה (na'avah) 'beautiful, comely, pleasant', as in the Song of Songs ('I am dark and beautiful'). The sense covers both 'beautiful' and 'pleasant/fitting'.