Narada Purana (Jyotisha Selections) · by Vyasa
Chapter 8 · Marriage
विवाहः
सुखं तत्रापि भामिन्यां शीलवत्यां स्थितं ततः ।तस्याः सच्छीललब्धिस्तु सुलग्नवशतः खलु ॥ ३९५ ॥
In the full Narada Purana (Purva Bhaga) this is chapter 56, verse 395.
Even there, happiness rests in a wife of good character. Her good character comes from a good lagna (rising sign).
Simple meaning: A wife of good character brings happiness, and a good lagna gives her that nature.
पितामहोक्तं संवीक्ष्य लग्नशुद्धिं प्रवच्म्यहम् ।
On a holy day, go to a calm, worthy astrologer to check the marriage lagna.
प्रणम्य देववत्पृच्छेद्दैवज्ञं भक्तिपूर्वकम् ।
The one asking bows to the astrologer and brings betel leaves, fruit and flowers.
तत्र चेल्लग्नगः क्रूरस्तस्मात्सप्तमगः कुजः ।
A bad planet in the lagna with Mars in the 7th may put the couple's life at risk within eight years.