Source 1: sworn testimony by american sergeant in congressional hearings
in 1969.
source 2: speech by american general touring the united states in 1969.
which do you trust more? why?

I trust “Source 1”

Explanation:  

I would trust the Source 1 i.e., the “Sworn testimony by American Sergeant in Congressional hearings in 1969” more because a sworn testimony is a gold evidence for the Congressional hearings. It won’t affect a person i.e., the Sergeant in any way. Maybe the testimony can get corrupted by lying, forcing and constraining, and the shaking the human memory. But in a speech by the General can affect his reputation as he can hid the truth and lie in his speech. So, the sworn testimony is more reliable than the speech.