I am not an expert because I am not interested in it.
I can't give a detailed explanation because I am not interested in it.
「詳しく説明できない」は英語で "I can't give a detailed explanation" または "I am not an expert" と言います。「興味がない」は英語で "I am not interested in it." と言います。
例文:
「私は興味がないので詳しく説明できません。」
"I am not an expert because I am not interested in it."
"I can't give a detailed explanation because I am not interested in it."
ご参考になれば幸いです。