re ‧ as ‧ sur ‧ ance /ˌriːəˈʃʊərəns $ -ˈʃʊr-/ BrE AmE noun
[uncountable and countable] something that is said or done which makes someone feel calmer and less worried or frightened about a problem:
Parents are looking for reassurance about their children’s safety.
give/offer/provide reassurance
They are offering practical help and reassurance.
reassurance that
We have been given reassurances that the water is safe to drink.