반신반의 (ban-sin-ban-e) – half in doubt/uncertain
This phrase has also the meaning of suspicion towards something or someone.
Add ~하다 for the verb form.
나는 반신반의하다가 그의 얘기를 들었어.
I was listening to his story while being half in doubt.
그 거짓말 자주 하는 여자의 모두 말을 반신반의로 받아야지.
I should take all of that often lying girl’s words with doubt.