In Buddhism what is love meant to be and how is it shown and can two people love each other?

The Beatles sang “All you need is love” in our times. Then there is another song on ‘Love’ that the celestial being, Pañcasikha, wrote to his ladylove in the time of the Buddha. Pañcasikha approached the Buddha and playing on his vinā, sang of the parts of the body of his ladylove that he loves as much as the Arahants love the Dhamma. The song that this Deva sang talks about both of the carnal love of passion, and of the altruistic love of the Triple Gem. Our question here is how we can see this other “Love” through Dhamma.

The love that we project in the loving-kindness (Metta) Meditation is the true love that one exercises toward oneself and others. We spread this other-worldly ‘love’ that is altruistic in nature in two ways. The two methods are Appamānha Chētō Vimukkti and Mahaggata Chētō Vimukkti. Loving-kindness meditation is meant to be a challenge for you to really think through as to why you would want to limit your love, and to remind yourself of why it’s good to have love for everyone. In this guardian meditation, we spread love direction-wise without any limit. Also we can spread loving-kindness by expanding the area of focus progressively.

As a person progresses deeper into Dhamma, he/she discards the false values in self, in cultivating awareness and a love that is altruistic and unselfish. When a person gets into the Noble Eightfold path, he/she rises above the "fetters" (samyojana) of (1) personality view, (2) doubt, (3) clinging to rules and rituals. This person is then possessed with qualities of honesty, uprightness, benevolence, altruistic joy, magnanimity, modesty and humility. The negative qualities of deceit, cunning, hypocrisy, jealousy, avarice, feelings of self-importance and arrogance are not found in one who begins to walk the Noble Eightfold Path. So to your question, Love still exists, but goes beyond to a level of limitless that is difficult to fathom.

On a conventional level metta (loving-kindness) means wishing all beings to be happy. It's unconditioned in a sense, since the love is not dependent on the being (i.e. whether it's someone likeable or unlikeable), but still deals with the concept of 'beings'.

Whatever beings there may be, weak or strong, without exception, long, large, middling, short, subtle, blatant, seen & unseen, near & far, born & seeking birth: May all beings be happy at heart - Metta Sutta

In ultimate reality there exist no beings at all (not even you exist). There is only the experience of one of the 6 senses (seeing, hearing, tasting, smelling, touching, thinking). So metta would here not refer to the concept of loving other people, but rather to the state of mind that is free from defilements (anger, greed, delusion). This aspect is mentioned at the end of the Metta Sutta:

Not taken with views, but virtuous & consummate in vision, having subdued desire for sensual pleasures, one never again will lie in the womb.

Understanding love is difficult unless you are already a very loving person. People who have lived through a dysfunctional or abusive family life understandably have a cynical or negative view of love. That is a very tragic situation for anyone to be in. But, if you want to observe someone in a very loving state, then you best observe the way a young infant loves his (or her) mother and father. Concerning the Tibetan concept of sunyata, it is best learned after you learn about love. For example, the Dalai Lama argues that the experience of sunyata does not deny the existence of anything. To understand why he says that is another story.

The Piyavagga & elsewhere refer to at least three kinds of love, namely:

(i) raga (lust);

(ii) pema; piya (affection; endearment);

(iii) universal or divine love & compassion (metta-karuna).

This is similar to the three kinds of love in Greek-Christianity, namely:

(i) eros (lust);

(ii) phileo (affection);

(iii) agape (self-sacrificing love).

People that realise the selfless ultimate reality love others with metta-karuna.