Letter to Ursula is a letter that can be found in Divinity II: Flames of Vengeance. It is located in a locked chest in the Hellish Dimension during the quest Seahorse Salad. It can only be obtained if you choose to fight Ursula instead of letting her go, and loot her key once she is killed.
|“|| My dearest sister,|
We are all eagerly awaiting your return, and hope you will be successful in your mission. I do not need to remind you how critical the spell you are seeking is to our battle. I am aware of the difficulties you're encountering and know all too well about the ludicrous behaviour of men, especially scholars who only come into contact with women once in a blue moon. You must keep at your task and not allow yourself to get distracted. I must insist that you keep your identity a secret and make sure you don't attract the attention of the authorities. Please come back to us quickly: Mother is getting impatient.
– Letter to Ursula, Divinity II: Flames of Vengeance