a shoulder to cry on idiom
C2 可以倾诉的对象，可以向其寻求安慰的人
someone who is willing to listen to your problems and give you sympathy, emotional support, and encouragement
I wish you'd been here when my mother died and I needed a shoulder to cry on. 我母亲去世的时候，你要是在这儿就好了，我当时需要一个可以给我安慰的人。