They show purvi getting ready for the marriage and she informs archu that she is ready with all smiles.. and then they show marriage taking place.. first arjun face was normal . they had a partition between arjun and purvi n wen the cloth came down, arjun's face reaction changed and they took the pheras and arjun took the kumkum and shown like keeping it on the gal with an upset face and manav and archana were stunned totally
Edit : Saw the promo again... Arjun didn't keep the sindoor on the gal. But his hands with sindoor were very close to the gals forehead.. And then they showed archana and manav stunned.
PS : Saw it only once... There might be mistakes.. They didn't show the gal who arjun was getting married.. But i'm 100% sure the gal is Ovi... The forehead and all that clearly shows its Ovi and hence ArMan are stunned. ðŸ˜ðŸ˜