To tell someone repeatedly in order to make them understand; to admonish, advise, or warn.
母は毎晩子どもに早く寝るように言い聞かせた。
Every night the mother told her child to go to bed early.
先生は生徒たちに安全ルールを守るよう言い聞かせた。
The teacher admonished the students to follow the safety rules.
大事な試験の前に『落ち着け』と自分に言い聞かせた。
Before the important exam, I told myself, 'Calm down.'
親は子どもにマナーを言い聞かせる責任がある。
Parents have a responsibility to teach their children manners.