The correct word to describe "意外惊喜" in English is "pleasant surprise".
A "pleasant surprise" refers to an unexpected and enjoyable event or experience that brings joy or happiness. It often catches us off-guard and brings a sense of delight and excitement. It could be a surprise gift, a visit from a loved one, or an unexpected achievement. A pleasant surprise has the power to elevate our mood, boost our spirits, and make us feel grateful. It adds a touch of wonder and magic to our lives. Such surprises are often cherished and remembered for a long time. They remind us to appreciate the small moments and find joy in life's unexpected blessings.