In Jainism, the primary focus is on living a life based on the core principles of ahimsa (non-violence), satya (truthfulness), asteya (non-stealing), brahmacharya (celibacy or chastity), and aparigraha (non-possessiveness). Jain teachings emphasize personal conduct, self-discipline, and spiritual development.

Having a non-Jain girlfriend is not directly described as a sin in Jain scriptures. However, Jainism encourages followers to associate with those who support and respect their spiritual path, as it is believed that the company one keeps can influence one's thoughts and actions. Relationships should be based on mutual respect, honesty, and non-violence.

If your relationship is built on these principles and does not lead you away from your spiritual duties or the practice of Jain values, it is not considered sinful. However, if the relationship encourages actions contrary to Jain vows (such as himsa or dishonesty), then it could be problematic from a Jain perspective.

It is also important in Jain tradition to consider the guidance of elders and spiritual teachers (gurus) when making decisions about personal relationships.

Ultimately, Jainism teaches personal responsibility for one’s actions and encourages self-reflection to ensure one's conduct aligns with its principles.