A person's looks are not as important as their personality.
It's what's on the inside that counts.
この場合、次のような言い方ができると思います。
ーA person's looks are not as important as their personality.
「人の見た目は性格と比べてそこまで重要ではない」＝「外見より性格が大事」
ーIt's what's on the inside that counts.
「大切なのは中身」
このような成句もあるので、一緒に覚えておくと良いですよ。
例：
When I think about what kind of woman I would like to date, I think it's more important what she's like on the inside rather than the outside.
「どんな女性と付き合いたいかを考える時、彼女の外見より中身がどのような人かがもっと重要だと思う」
ご参考まで！
”外見よりも性格が大事"
- Personality is more important than appearance.
- Character is more important than appearance.
- Personality is more important than looks.
彼女の性格を外見より重視しています。
- I value her personality more than her appearance.
カナダ 
アメリカ合衆国 
