I used G'MIC-Qt / Artistic / Highlight Bloom. Set the sliders to get the best result and then repeat the G'MIC-Qt filter a few times (Filters / Repeat G'MIC-Qt)
Another solution : Filters / Gaussian Blur (value 4) and then use the curves.
You can search a similar script font here : https://www.dafont.com/mtheme.php?id=6
Another solution : Filters / Gaussian Blur (value 4) and then use the curves.
You can search a similar script font here : https://www.dafont.com/mtheme.php?id=6