Ensure you do not have conflicting dialogue mods loaded for Jas at the same time.
Not every player who wants more Jas content is looking for a marriage mod. The Stardew Valley modding community has created several excellent alternatives that expand Jas's character without crossing into romance territory. stardew valley jas marriage mod top
Instead, it dramatically expands her story and character, adding heart events (at 2, 4, 7, 8, and 10 hearts) and hundreds of lines of new dialogue. You get to help Jas learn about her family history and decide her future in a wholesome, platonic way. For players who love Jas's character, this is the "top" mod to get. Ensure you do not have conflicting dialogue mods
Downloading files from unknown sites carries significant risks. Instead, it dramatically expands her story and character,
— run StardewModdingAPI.exe (not the normal game executable) to play with mods enabled.