What is the test for credibility of a witness in a civil case?

a witness, and a very beneficial plea bargain after his first jury deadlocked. Defendant argues that such evidence showed that Doe came forward because he expected something in return for his information and knew from having received benefits in the past that he could manipulate the system. As our review is deferential, we must accept the trial court's resolution of credibility conflicts. (People v. Tully (2012) 54 Cal.4th 952, 979.) Moreover, a witness does not become a government agent simply by coming forward with information, even if he subjectively believed that he would benefit by doing so. (Dement, supra, 53 Cal.4th at p. 33.)