“Σας έχω πει πόσο όμορφα είστε;”, the speaker is addressing a single person in a formal or respectful manner. The use of “όμορφα” indicates that the speaker is using the neuter plural form, which is appropriate in formal contexts when addressing someone respectfully, regardless of their gender.
So, the translation could be understood as: “Have I told you how beautiful you are?” This could apply to either a male or female individual, and the formality is conveyed through the use of "σας.”
Unfortunately in this case the AI’s explanation is entirely wrong and misleading. If it was indeed addressed to a single person in a formal manner, it would have to be:
Σας έχω πει πόσο όμορφη είστε; / Have I told you how beautiful you are? [to a woman]
Σας έχω πει πόσο όμορφος είστε; / Have I told you how beautiful you are? [to a man]
Using όμορφα in this sentence makes sense only if it’s addressed to a group of neuter nouns, for example:
Κορίτσια! Σας έχω πει πόσο όμορφα είστε; / Girls! Have I told you how beautiful you are?
I wish people were aware of this, but sadly it’s the opposite - despite of being warned about it multiple times, the author of this post keeps spamming the forum with AI generated misinformation and hasn’t reacted even once when it was pointed out to him. All that with the silent approval from the admins (or even encouragement, since some of my posts about it have been censored and removed, while none of his posts has ever been addressed in any way). It reached the point where I simply gave up and stopped correcting them, so they are now cluttering the forum and, sadly, making it unusable for modern Greek learners.