It is impossible for real love to exist unless it is accompanied by fear.
When love is serious, it is necessarily accompanied by an aspect of fear, which is the fear of losing the beloved.
This is true in a relationship between people and in a relationship between a person and anything else, even an inanimate object that cannot see or feel.
When a person has a relationship of affinity toward something, there is perforce also a relationship of respect toward that thing. People have this kind of relationship with work, with beauty, with animals, and even with food and drink.
A person who has an affinity for good wine will treat it with a certain amount of respect.
One who has an appreciation for special foods will shudder if two different kinds of foods that do not belong together are mixed.
Additionally, any situation in which there is love without fear, or the opposite, indicates a flaw, a falsehood or corruption in the relationship.
Rabbi Adin Steinsaltz