From the RTFM:
Sims should no longer automatically and instantly fall in love at the first flirt. Chance of being hit with hearts now depends on attraction level and is influenced by aspiration and personality.
Since your sim has only 1 bolt attraction, it could take a while. The sims' aspirations and personalities may also not be particularly compatible.
If you see this as a problem, you could remove noinstantloves and test whether your sim falls in love. Once that is done, reinstall the hack. If that is too "cheaty" for you, you may just have to get her to work really hard on the romancing.