: Ensure your Steam launch options are configured to run SMAPI so your mods activate when you play. Jas marriage mod | Chucklefish Forums
If you can't find a dedicated Jas marriage mod, you can use (sometimes called "Platonic Partners"). This lets you give a bouquet to any NPC, but it won't add custom events or aged-up sprites – Jas will still look/act like a child, which is jarring. stardew valley jas marriage mod download
: Almost all modern character expansions require the Stardew Modding API (SMAPI) to function. : Ensure your Steam launch options are configured