grain of truth
element of truth

The hard fact is, there's some small element of truth in that.

On the other, there was an element of truth in what Kelley had said.

There are elements of truth in the statements by both men.

But there was an element of truth to his words.

And there was an element of truth in what he had said.

And maybe there was an element of truth in that.

Very likely there is an element of truth in both suggestions.

And there is some element of truth in these perceptions.

There was an element of truth to what he'd said.

Certainly, there is an element of truth in the comparison.