You got it. 了解
I've never heard of it. 聞いたことがない
メインストリートにある新しいレストランの事聞いたことがあるわよ
I've heard of the new restaurant on main Street.
こんなにかわいい女の子今まで見たことないよ
I've never seen such a cute girl before.
Innocently or maliciously 悪意が無くてもあっても
Innocently means without any bad intentions. Maliciously means with the intent to cause harm.
Succinct 簡潔に
Speaking or writing briefly and precisely without any extra unnecessary words. Such as she had prepared a succinct explanation about the new marketing strategies. Or her proposal was succinct but very informative.
Without fail 確実に 完璧に
Collin is referring to something that always happens. He turns in the sale report on the last day of every month without fail. "Don't worry I will do it without fail."