Fiance compliments before nikah

From an Islamic perspective, khiṭbah (engagement) does not constitute marriage, so the fiancé and fiancée remain non-maḥram to each other before the nikāḥ.

Therefore, as a matter of precaution, it is not appropriate to make statements that express love, romantic attraction, or emotional intimacy, such as: “I prefer hearing your voice,” especially if such words may increase emotional attachment or desire, or lead to prolonged and unnecessary conversation.

Allah Almighty says:

فَلَا تَخْضَعْنَ بِالْقَوْلِ فَيَطْمَعَ الَّذِي فِي قَلْبِهِ مَرَضٌ

“So do not be soft in speech, lest the one in whose heart is a disease should be tempted.” (Al-Aḥzāb: 32)

And Allah knows best.