Dictionary / Vocabulary / 買いかぶる
かいかぶる
to overestimate (someone); to overrate; to think too highly of; to make too much of
Also written 買い被る
彼女は私の能力を買いかぶってはいない。
She has no illusion about my ability.
君は彼のことを買いかぶっている。
You overestimate him.