Is there scientific evidence that true love exist?
Some things can be observed but not measured
I don't know what is science's part in this matter. Love feelings are caused by spirits. Spirits determine the destiny of the human beings from humans' daily activities, talks and thoughts too. All spirits (good and bad) have the dominating character. They can take you to the extent of sacrifice or suicide. True love occurs when the minds of the lovers are same. They can do any kind of sacrifice for the welfare of the each other. That means, true love exists. You must also know this. Spirits are separate elements. A human being is not a single spirit. A human being doesn't have a spiritual body. A human being during his/her lifetime is living with many spirits which have joined one by one since birth. They are knowledge, skills, feelings, emotions, interests and everything. Even thoughts are not your own. For example, when you want to take a decision on a subject, one after another the spirits think and you just listen, choose or reject the ideas which they transmit to your mind through your brain in the form of thoughts. Brain is just a media to connect the spirits to your mind. A mind is just a computer's mind. After the destruction of a computer completely you will not get it's mind. The same is the case with the human beings. Soul is nothing but an energy needed for the functionality of a body. It is not a spirit or anything else. All human beings are just robots made of flesh and bones and toys of the spirits for their games.
modern science shows that populations genetically-select for domesticity and altruism; this is why we have churches, communities, couples and families.
True love does not require evidence, because feelings cannot be explained by science.
'True love'? No. It is a value judgement, not a measurable phenomenon. 'Falling in love', yes, it can be measured by the release of certain hormones in the brain. There is a cascade of these hormones early in the relationship which is the real 'falling in love' feeling. There is nothing quite like it. The level of the hormone drops over the course of 2-3 months by which time the couple will be 'pair-bonded' or not. That's why some relationships fade after 2-3 months. The party comes to an end and they find there is not enough to keep them together.
What is the difference between regular love and true love?
No but there's scientific evidence that love is just an instinct that urges us to reproduce and care for our closest of kin.