>>30143329Because while Lillie love Sun, she isn't sure what he think of her. From her perspective, she just caused trouble for him. She is too scared to confess.
Even if she had confessed and Sun had accepted her feelings, she would be have to tag along with him as a beginning trainer, causing him even more trouble. That's why she wants to become a trainer first. She wants to become strong in hopes that Sun will respect her a little and accepted her feelings. So that she can be with him forever and ever without holding him back.
It's really cute. I'm so glad GF actually put some thought into this.
