Well, actually, you can.
Love is the name we give to an hormonal reaction of our body when we are in relation to some individuals. By simply mesuring the level of ocitocine in your blood, you can measure the amount of love you have for someone.
This is not really the point of the discussion but it is interesting because your argument is basically : “I have no idea how *this* can be rationnally proved thus nobody can prove it”. Which is often used by religious people.
Then, as most religious people, you add “and because nobody can prove it, it proves that god exists”. (an argument for which I still can’t find the logical reasoning)