There are many synonyms for the phrase "marked deeply" that can be used to express the emotional impact or significance of something. Some possible options include "etched firmly," "engraved profoundly," "imprinted strongly," "stamped indelibly," "scribed intensely," "carved deeply," "inscribed deeply," and "written indelibly." These words evoke a sense of permanence, importance, and intensity, suggesting that whatever has been marked deeply has left a lasting impression on the individual or situation. Whether it's a memory, emotion, or physical mark, using strong synonyms can help to convey the power and significance of the experience or event.