When did Sandstorm learn that she loved Firestar?

The answer is not entirely clear, but it mostly started when Firestar saved her in the battle with RiverClan, before she fell off the gorge in the second book in the original Warriors series, Fire and Ice. She began to realize that he wasn't such a bad cat after all and started paying more attention to him rather than torturing him with Dustpaw. She soon started to fall in love with him when she realized that they had similar personalities, similar ages, and that he was a very handsome tom.