Does telling a daughter what her mother told her in private lead to sin, given that the mother did not ask her to keep it a secret?

If there is an indication that the mother wished to conceal what she told you, or if it is something that is typically kept secret, then spreading it is considered a sin. However, if it is not so, then there is no sin upon you. Disclosing a secret is forbidden if one is commanded to keep it confidential, or if there is an indication to that effect, or if it is something that is typically kept secret. Indeed, it is stated in the Hadith: "Assemblies are by trust except for three types of assemblies: shedding unlawful blood, committing unlawful sexual intercourse, or unlawfully seizing property," and "If a man tells another man a narration, then looks around, it is a trust," and "Whoever hears a narration from a man that he dislikes to have mentioned about him, it is a trust, even if he did not explicitly ask him to keep it secret."