I got an email from my boyfriend that was kind of matter-of -fact. It was quite impersonal actually.
この場合、次のような言い方ができますよ。
ーI got an email from my boyfriend that was kind of matter-of -fact. It was quite impersonal actually.
「彼氏から何となく事務的なメールが届いて、結構冷たく感じた」
matter-of -fact で「事務的な」
ご参考まで!