This would be in the context of a romantic relationship/partnership. My overarching view of this is that I feel like in our times and culture those words have become very cheap. Seeing people treat each other like total garbage and try to put a band-aid on things by saying the magic words. Can love not be expressed by your actions, your nature, and your respect towards another person? I know when someone loves me, they don’t have to tell me also.
Well if you love someone and they say it to you first, then you should probably say it back. Unless you’re Han Solo and you are cool enough to get away with saying “I know.”