Is there a way to sell my unity license to another person, i don’t have time enough for developing in Unity ?
Or is there a moneyback garantuee 
Regards and thanks,
Jasper
You should write such questions to support@unity3d.com instead of posting em on the iPhone forum.
As per the End User License Agreement you accepted upon installation Unity licenses are not transferable. Therefore you cannot sell you license to someone else, sorry.
If you have questions about this then please feel free to ask here or by email.