C2 adjective /ɪnˈɡreɪʃiˌeɪtɪŋ/
ingratiating
schmeichelhaft
Meaning
Charming or flattering in a way intended to gain favor.
Example
His ingratiating smile made everyone trust him quickly.
Sein schmeichelhaftes Lächeln brachte alle dazu, ihm schnell zu vertrauen.