Answer:
It is permissible, but under certain circumstances it is forbidden.
Explanation:
Think about Romeo and Juliet, their love was forbidden and that's why the went to such great lengths to keep it, but in the end, they did not get to enjoy because they died.
But for a modern day example, think about gay couples, they love each other but in some countries it is forbidden. They can't love each other with out suffering the consequences.
That only describes romantic love. Platonic love, on the other hand, is always permissible. You are always welcome to love others and show your love. For example, giving people gifts is a way to show love, and it is always permissible. There is no law against being nice.
I hope this long explanation actually helped answer your question in some way.
