The Book of Marriage
Ṣaḥīḥ Muslim 3543
إِنَّ مِنْ أَعْظَمِ الأَمَانَةِ عِنْدَ اللَّهِ يَوْمَ الْقِيَامَةِ الرَّجُلَ يُفْضِي إِلَى امْرَأَتِهِ وَتُفْضِي إِلَيْهِ ثُمَّ يَنْشُرُ سِرَّهَا
inna min aʿẓami al-amānah ʿinda-Llāh yawma al-qiyāmah ar-rajula yufḍī ilā āmraʾatihi watufḍī ilayhi thumma yanshuru sirrahā
Transliteration generated from the Arabic vowel marks
The full narration
Abu Sirma al-Khudri (Allah he pleased with him ) reported Allah's Messen- ger (ﷺ) as saying:The most important of the trusts in the sight of Allah on the Day of judgment is that a man goes to his wife and she goes to him (and the breach of this trust is) that he should divulge her secret Ibn Numair narrates this hadith with a slight change of wording
Source
Ṣaḥīḥ Muslim · 3543
Ṣaḥīḥ