Oui, mon amour.
Here's a breakdown:
* Oui: Means "yes"
* mon: Means "my" (masculine)
* amour: Means "love"
You can also use other expressions like:
* Oui, ma chérie: "Yes, my darling" (more affectionate)
* Oui, mon cœur: "Yes, my heart" (more poetic)
The best way to choose depends on the context and your relationship with the person.