Can a girl's wish to enter Paradise be combined with a cartoon character, and her wish to marry a committed young man and enter Paradise with him, and is there anything she should do to achieve this, especially if her supplication is not answered in this world?

Attachment of the heart to a cartoon character and wishing to meet them in the afterlife is strange and impermissible, as they are not real and not among the people of Paradise. This could be from the stratagems of Satan. One must divert the heart from thinking about this and strive in obedience to Allah. Cartoon films often contain শরعي (Shari'i) prohibitions, such as music, and watching them is a waste of precious time. As for wishing to marry a specific young man due to his religiosity and good character, there is no objection to supplicating for that and seeking to marry him according to Islamic guidelines. If that is not facilitated, it is recommended to occupy oneself with what is beneficial and useful and to entrust the matter to Allah.