I need a thesis/concept sentence and a topic sentence on the theme 'power and passion of young love'.

I think that with the construction of any thesis
statement, you would have to go back to the original task or writing assignment and see
if there are certain elements that have to be integrated within it before you start
composing your statement.  Once you have done this, I think you should be able to
proceed away.  From a general standpoint, you could probably go in a variety of
directions with the idea of young people in love.  I think that you need to define what
you consider to be "power" and "passion."  In defining these terms in more specific
contexts, textual support can be used in explaining their implications.  An argument can
be made that it is the youthful zeal of both of them that ends up bringing the families
together at the end or that causes them to break family convention and seek to be with
one another in the first place.  An argument could also be made that the feelings of
love that both youths share does not really solve anything, as Romeo still kills even
though he is supposedly in love with Juliet.  He might feel awful about it, but the fact
remains, at that moment, familial bonds trumped young love.  I think that assessing what
is needed from the original assignment and then defining some of the terms in the thesis
in clearer contexts will help in constructing a solid thesis
statement.