To prove love, you need to define what love is. If you cannot define love, you cannot prove it.

1. a physiological motivation such as hunger, thirst, sleep, and sex drive
2. a strong feeling of warm personal attachment or deep affection, such as for a parent, child, friend, or pet
3. is having a companion, best friend, lover, partner, sounding board, cheerleader, advisor, and cuddle buddy through every avenue in the journey of life
4. is completely opening up and sharing your feelings and life with them daily, that’s what constitutes a healthy relationship. But, it must be mutual. If a particular area is lacking on either side of the relationship, it makes it unideal and unhealthy.

Let us say you define love by certain parts of the brain which are active. From there you can compare the results for every tested individual. When you become attracted to another person and are “falling in love,” the brain triggers an increase in the hormones dopamine and norepinephrine. Dopamine, the “feel-good” hormone, increases levels of happiness and satisfaction as your attraction grows. 

Is this enough to prove that love exists?

Yes and no:

It is hormones and neurotransmitters acting up in your brain. Researchers have scanned the brains of people who are madly in love and found a heavy surge of dopamine, a neurotransmitter in the brain’s reward system that helps people feel pleasure
People in love regularly exhibit signs of emotional dependency on their relationship, including possessiveness, jealousy, fear of rejection, and separation anxiety. They also long for emotional union with their beloved, seeking out ways to get closer and daydream about their future together.
What is the true test of love? True love is a sense of absolute affection and warm feelings towards a person and does not get altered easily. You love a person truly when you are willing to give up your happiness for theirs and love them for who they are, warts, ugly fashion choices and all.