According to Osho, fear arises with love because love is a kind of death: your old personality and ego must dissolve so a new being can be born. This shadow of fear is natural; it signals transformation, not danger. Instead of hiding, allow the ego to die—accept vulnerability. Only through this inner crucifixion and resurrection does the real taste of love become available.
Feeling scared when you love means your pretend self is breaking so the real you can come out—let it happen instead of running.