Is love the subject here? I don't understand it because of verb to be.
The simple answer to your question is, "yes."
In any simple "to be" sentence, the subject is always to the left of "to be."
I will go. (subject: I)
You are wonderful! (subject: you)
That is amazing! (subject: that)
It was over there. (subject: it)
Only when you get to more complex sentences will you find the subject to the right. Questions are good examples:
How is that possible? (subject: that)
Where has the time gone? (subject: time)
Who was that man? (subject: man)