Antonyms for the phrase "strikes terror into" would be words that suggest a calming, soothing or pacifying effect on the mind or emotions. Such words may include comfort, reassurance, calmness, relaxation, confidence, and joy. When something strikes terror into a person, it creates a sense of fear, panic, or overwhelming anxiety, but the opposite of this would be a feeling of ease, serenity, and contentment. Antonyms can help us to understand the opposite of a word or a phrase, and they are useful for creating contrasting effects in writing, speeches, and conversations.