a rather simplistic one : grief drives her , love drives him 
(ROOT (NP (NP (DT a) (ADJP (RB rather) (JJ simplistic)) (NN one)) (: :) (S (S (NP (NN grief)) (VP (VBZ drives) (NP (PRP her)))) (, ,) (S (NP (NN love)) (VP (VBZ drives) (NP (PRP him)))))))
(ROOT (NP (NP (DT ) (ADJP (RB ) (JJ )) (NN )) (: ) (S (S (NP (NN )) (VP (VBZ ) (NP (PRP )))) (, ) (S (NP (NN )) (VP (VBZ ) (NP (PRP )))))))