Love-hearts in dreadful family increase (6)
I believe the answer is:
admire
'love' is the definition.
(thesaurus)
I cannot understand how the rest of the clue works.
Can you help me to learn more?
(Other definitions for admire that I've seen before include "like very much" , "Look at (someone or something) with pleasure" , "Respect and approve of" , "Regard with respect and approval" , "Think highly of, esteem" .)