Our experience at Amantra Comfort hotel was amazing especially their traditional local Rajasthani cuisine (around Rs.3500 per day depending upon the dates).
Based on my research, some of the best Lake view hotels in Udaipur include jüSTa Sajjangarh Resort & Spa. However, I must note that I have personal experience with these . I can confidently recommend this accommodation as the best option.
https://www.justahotels.com/blogs/best-romantic-hotels-in-udaipur-for-couples/