ややきつめの目つきをしているものの根は奥手で純情な性格。
Is this right
My translation is: even though here appearance looks serious she is still undeveloped at the core thus having an innocent personality
**
ややきつめの目つき
** What does it mean ?
「ややきつめの目{め}つき」
やや ＝ 少{すこ}し ＝ slightly
きつめ ＝ きつい (harsh, intense) + め (~ish, on the ~ side)
The form is 「Adjective Stem + め」.
The confusing thing here is that this suffix め can also be written 目 in kanji. Thus, we actually have two 目's in this phrase with only the second one meaning "eyes".
目つき = one's look or expression
Putting it altogether, we have:
"A look/expression that is slightly on the intense side"
Finally, your interpretation of the sentence is actually quite good.
My translation attempt is: At first glance, her appearance looks a bit stern, but actually she is just shy and innocent.
I believe your interpretation of the sentence has no problem at all.
ややきつめの目つき means she has somewhat sharp and stern eyes, basically describing her appearance as not very friendly-looking.
根は in this sentence means "essentially" or "actually," depicting her true personality in the ensuing segment 奥手で純情な性格.
奥手 more literally denotes "unsophisticated," but I believe it is more close to "shy" in the sentence.
