To give (someone) confidence in the trustworthiness of (something).
To reassure.
To make sure and secure; ensure.
To do something to (a person) that they are not expecting, as a surprise.
To attack unexpectedly.
To take unawares.
To cause (someone) to feel unusually alarmed or delighted by something unexpected.
To undergo or witness something unexpected.
To cause surprise.
The feeling that something unexpected has happened.
Something unexpected.