to win the support, goodwill or friendly feelings of (a person, country etc); calm the anger (of a person, government etc)

placate

to make a person feel certain, cause a person to realize

gain the confidence of

to persuade or influence (a person); to cause, bring, about (something)

cause to happen; encourage

to make (a person) feel certain about, believe something

cause to believe; convince to do

to make (a person) feel less angry

soothe, pacify

to become friendly with (a person) after a quarrel

make peace; adjust