"Extra reassurance" means providing an additional sense of comfort or confidence to someone, to make them feel more secure or sure about something. Full definition
Blind - spot monitoring was flawless and much appreciated, particularly in the rain, when it provided extra reassurance during lane changes. (cnet.com)
Since there was no travel insurance back then, they needed extra reassurance. (travelinsurancereview.net)
To offer extra reassurance to those larger clients, join a professional body within your industry — something that proves you're certified in your profession. (creativeboom.com)