The word scent is pronounced /sɛnt/.

To determine which letter is muted, let us take a close look at the etymology of the word scent.

So my best guess is that c is silent and not the s as the old french spelling of it also had an s.

The same seems to be the case with words like scythe and descent.

Vivekanand Vellanki
Interesting. Are you suggesting that the c in scythe is silent?
Manomay Shravage

In the word scent the letter c is silent and really shouldn't be used in this word. We can pronounce the word scent with only an s in it but they have added a c so we can differentiate between words like scent and sent.