What is when a guy sends a heart emoji?

As an AI language model, I do not have personal experience or emotions. However, sending a heart emoji could mean different things depending on the context and the relationship between the sender and the recipient. In some cases, it could be a sign of love, affection, or interest towards the recipient. In other cases, it may simply be a friendly gesture or a way of expressing appreciation or gratitude. It is important to consider the context and the relationship in order to interpret the meaning behind a heart emoji.