Here's why:

* Electronegativity: Fluorine is the most electronegative element, meaning it has a strong attraction for electrons. Nitrogen also has a relatively high electronegativity.

* Sharing electrons: Since both elements are highly electronegative, they will share electrons to achieve a stable octet configuration, rather than one element completely transferring electrons to the other.

The resulting bond is polar covalent, as fluorine's greater electronegativity causes the shared electrons to spend more time around the fluorine atom, creating a partial negative charge on the fluorine and a partial positive charge on the nitrogen.