To remove someone's doubts or fears; to comfort.

आश्वस्त करना

English Usage: She tried to reassure him that everything would be alright.

Hindi Usage: उसने उसे आश्वस्त करने की कोशिश की कि सब कुछ ठीक रहेगा।

The act of removing someone's doubts or fears; comfort given to someone.

आश्वासन

English Usage: He needed some reassurance that he was making the right decision.

Hindi Usage: उसे यह आश्वासन चाहिए था कि वह सही निर्णय ले रहा है।