The adverb strongly is useful for describing something that's done powerfully or forcefully. When a teacher speaks strongly, the class pays attention.
If your parents strongly advise you not to borrow their car unless it's an emergency, they really mean it. When your friend says that she strongly dislikes roller coasters, it means she would not enjoy a surprise trip to an amusement park as a birthday present. Strongly means "with strength," and it comes from the adjective strong, with its Old English root word, strang, "physically powerful, forceful, or severe."