I came across the sentence 我觉得你说的是真的 in my studies, which I was told translates to "I think what you say is true". I'm not sure how you parse this sentence though. In particular, what function do each of the 的 serve?
'我' (I) is the 'subject'
'觉得' (think) is the 'verb'
'你说的(话)' (the words you said) is the 'object'
'是' (is/was) is 'auxiliary verb'
'真的' (true) adjective
'你说的' is shortened from '你说的话', which is the object
I think the words you said were true.
I think that the words that you say, those are true words.
I think what you say is true.