Hans, who is an incredibly kind, decent and patient man, easily wins over Liesel's affections after she comes to the Hubermann household. He does this through several different acts of kindness, all of which help Liesel to feel loved, supported, and okay with who she is.
Liesel is afflicted with horrible nightmares about her brother's death. Every single night, she sees his body in her dreams again, and wakes up screaming from the trauma that created within her. Hans, every single night, goes in to her and comforts her while she calms down and is able to go back to sleep. He hugs her, speaks soothing words, listens to her, and stays with her for hours. This helps Liesel to feel loved instead of like a burden. Hans demonstrates total patience and love for her through this hard time.
Also, Hans teaches Liesel how to read and write--Liesel, who doesn't know how, snatches books that Hans then patiently teaches her to decipher. He does this during their nightime nightmare hours, and also in the basement, using Hans' paints to teach her how to write. He is incredibly patient, as this is a very difficult and slow process, and he never shows impatience or frustration with Liesel's slow progress. One last way that Hans shows love is by shielding Liesel from the more gruff style of Rosa, joking with Liesel, and teaching her through example how to respond to Rosa's rather unconventional way of dealing with her.
Overall, Hans is a stabilizing and life-saving force in Liesel's life, one that allows her to overcome the difficult circumstances that she has faced, and be strong. I hope that those thoughts helped; good luck!
In the book The Book Thief Hans is such a kind and caring man that it is easy for him to gain Liesel's love. She is in a new home and alienated from the mother that she loved. She needs one person with whom she can attach. Rosa is a harsh female. She is very dominating and negative. She curses at Hans and Liesel, but she does love them. She is beat down by poverty and hard work. Hans is the opposite. He looks for the best and does what he can to help others.
The first thing that Hans does is he watches over Liesel. Liesel is frightened at night. Hans spends time sleeping by her even though it is uncomfortable for him. He sits and sleeps so that when she awakens she will feel safe. He also teaches her to read. Liesel loves to have him read to her. At Christmas when they have no money he even finds a way to get her a book. His music is another key to establishing a relationship with Liesel. He loves to play music for her. Hans proves himself worthy of her love even more, when he takes a stand by honoring a favor to someone and helping the Jewish man by hiding him.
Hans is the older father that Liesel has not known before.