It literally translates as "Mine is yours," but it's often used to express:
* Giving something: "Take it, it's yours."
* Sharing: "We can share it, it's yours too."
* Giving freely: "I'm giving it to you, it's yours now."
It can also be used in a romantic context to express:
* Devotion: "I'm yours, everything I have is yours."
The exact meaning will depend on the context.