at first blush
Also, at first glance or sight. When first seen. For example, At first blush we thought it was an elegant restaurant, but it soon became obvious that it was hardly the place for a special dinner, or At first glance the contract looked just fine. All three phrases date from the 1300s. The noun blush is used with the obsolete meaning "glimpse" or "momentary view" and in this idiom has nothing to do with showing embarrassment. Also see love at first sight.