This one is really, really hard, but I hope I did good on it for you!
While Obito was “missing/dead”, he would send Shizune a Valentine every year and a gift on her birthday. Even while she traveled, she would get presents and always said that Obito never died. Kakashi thought she was in denial, but never pushed her. Rin was too sad to respond.
One time, when Shizune had a horrible fever, Obito skipped training for a whole week and took care of her. Minato wasn’t too pleased and Kakashi gave him shit about it, but both guys forgave him when Shizune came to training all better and hugged Obito.
Whenever Obito was down in the dumps about not meeting Kakashi’s level, Shizune was the only one to cheer him up by making him dinner and a kiss on the cheek.
Obito was always nervous whenever he saw Rin and Shizune talking, because he thinks Rin is telling Shizune embarrassing stories about him on missions.
Obito was the first to congratulate Shizune when she decided to become a medical ninja.