Loyalty
noun, な adjective
I have sincerity about my loyalty. That shows loyalty, right?
ちゅうせい
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
今振り返ってみると、ハチ公は絶対的な忠誠心を持ったいい犬だったよな。
Looking back, Hachiko was a dog that had absolute loyalty.