The Nobility, A Noble
noun, の adjective
People of a valuable tribe are part of the nobility. Unlike our tribes, they are valuable.
きぞく
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
ああ、もし私が貴族の家柄に生まれていたら、彼女と話をすることも可能だったかもしれないのに。
If I had been born to a noble family, I would have been able to talk to her.