Q: I lit a fire that burned a neighbor’s storage room. He claims to have stored there valuable works of art worth $100,000. Who has the burden of proof?

A: Generally, we follow the dictum ‘hamotzi mechavero alav hara’ayah’ (the burden of proof is on the plaintiff). However, Chazal instituted that in certain cases of monetary damage, fire, bodily injury or robbery, we believe the damaged party with an oath regarding the amount of the damage — if the amount is reasonable for the person in question and the circumstances of the damage (see C.M. 90:1; 388:1; 418:13; Pischei Choshen, Nezikin 10:36-39).

Thus, a wealthy person would be believed with an oath; one not regarded as wealthy would not be believed without witnesses or evidence [unless he can verify that he served as a guardian for someone liable to have entrusted such an item]. If the perpetrator definitively denies the amount claimed, the damaged party is not believed even with an oath in the case of a fire, but is believed in the case of robbery (Shach 388:1, 3; 418:7).

As mentioned previously, beis din discourages swearing nowadays and strives to mediate a compromise on the matter.