Will painting over mold work?

No. Paint hides the color until the moisture pushes it back off, often as bubbles or a stain in the same shape. On a stone wall, the wrong coating also traps the damp that used to evaporate. Kill the water, remove or clean the growth, dry to a meter reading, then paint if you still want to.

A fresh paint smell in a basement on a home tour is a question, not a comfort. Ask what was under it.