From Longman Dictionary of Contemporary EnglishI know (just/exactly) how you feelI know (just/exactly) how you feelspokenKNOW something used to express sympathy with someone or with a remark they have just made I know how you feel, Mark, but maybe it’s better not to confront him. → feel
Examples from the Corpus
I know (just/exactly) how you feel• I have a sudden urge to touch her, to hold her, to tell her I know how she feels.• You ran a decent campaign, John, and I know how it feels to lose.• I know how you feel about it ... You would rather wait - wait till we're married.• I knew how he felt about me -- a short blind boy who hated leather basketballs.• I know how he feels about me!• I know how you feel, Doyle thought.• I know how you feel, they're all or nothing.