What does Numbers 5:16 mean?

and a man lies with her carnally, and it is hidden from the eyes of her husband, and this is kept concealed, and she is defiled, and there is no witness against her, and she isn’t taken in the act;

and the spirit of jealousy comes on him, and he is jealous of his wife, and she is defiled: or if the spirit of jealousy comes on him, and he is jealous of his wife, and she isn’t defiled:

then the man shall bring his wife to the priest, and shall bring her offering for her: one tenth of an ephah of barley meal. He shall pour no oil on it, nor put frankincense on it, for it is a meal offering of jealousy, a meal offering of memorial, bringing iniquity to memory.

and the priest shall take holy water in an earthen vessel; and of the dust that is on the floor of the tabernacle the priest shall take, and put it into the water.

The priest shall set the woman before Yahweh, and let the hair of the woman’s head go loose, and put the meal offering of memorial in her hands, which is the meal offering of jealousy. The priest shall have in his hand the water of bitterness that brings a curse.

The priest shall cause her to swear, and shall tell the woman, “If no man has lain with you, and if you haven’t gone aside to uncleanness, being under your husband, be free from this water of bitterness that brings a curse.