Formal:
* صبح بخیر عزیزم (Sobh bekheir azizam): This is the most common and polite way to say "good morning darling". "Sobh bekheir" means "good morning" and "azizam" means "darling" or "my dear".
Informal:
* صبح بخیر عشقم (Sobh bekheir eshgham): This is a more affectionate way to say "good morning darling", using "eshgham" which means "my love".
* صبح قشنگت بخیر (Sobh qeshanghet bekheir): This translates to "good morning your beautiful day" and is a very sweet and romantic way to say "good morning darling".
Intimate:
* صبح بخیر جونم (Sobh bekheir joonem): This is a very affectionate and intimate way to say "good morning darling", using "joonem" which means "my life" or "my soul".
You can also use a combination of these phrases, such as "صبح بخیر عزیزم جونم" (Sobh bekheir azizam joonem) which means "good morning darling my life".
Ultimately, the best way to say "good morning darling" in Farsi depends on your relationship with the person you are speaking to.