Are you sure that the second blank ‘supports’ the word ‘genial’? - yeah I think because of the word ‘and’ , I might be wrong here.
What is the entire sentence trying to tell you? How is it structured?- for this I looked from ‘an enigma ….vexing.’, so the structure tells me that she has diferent shades in her personality hence, contradiction in her personality, so’contradiction’ fits third blank.
For the first two blanks we should see words which related to facinating and vexing
for first blank: it has ‘and severe’, so something supporting the word ‘severe’ should come here, which should be realted to word vexing , so I went for stubborn (stubborness can be irritating)
for the second blank : teh word should support genial , which means warm freindly so I went for accessible.