This is Peninnah, the other wife of Elkanah. A rival is someone who competes against another person. In this case Peninnah was competing against Hannah to try to get Elkanah to love her best.
These rhetorical questions can be translated as statements, if necessary. AT: "Hannah, you should not weep. You should eat, and your heart should be glad because I am better to you than ten sons!" or "You have little reason for sadness. I favor you and that should be enough." (See: [[rc://en/ta/man/translate/figs-rquestion]])