Yes, marriage is possible between two people with the same surnames even if they are not siblings. The reason is that surnames are inherited and can be shared by unrelated individuals who belong to the same extended family or community. People with the same last name may have common ancestors, but it's not a strict requirement, and it's entirely possible for unrelated individuals to share the same surname.
Marriage laws and regulations regarding the use of surnames can vary from country to country, and in some cultures, marrying someone with the same surname might be discouraged due to concerns about potential genetic issues or the perception of close family ties. However, in many places, there are no legal restrictions on marriage between individuals with the same surname as long as they are not close blood relatives like siblings or first cousins.
It's essential to understand that marriage laws and social norms differ worldwide, so if you find yourself in such a situation or are considering such a marriage, it's best to consult with legal and cultural experts in your specific region to ensure you are compliant with the local laws and customs.