Question about imprinting???

Yes. Renesmee can fall in love with someone else. Stephenie Meyer claims her books are about choice. Jacob doesn't have an option. Renesmee does. She is not attached to Jacob in anyway.

However, it is also said in the book that the person who is imprinted probably won't refuse that love. Reason: because how can someone refuse one who has been with them and supporting them for all those years. In Eclipse, it's explained more with Quil and Claire's story.

Hopefully my answer was satisfactory? :)

You might want to look up imprinting but No I don't think That Nessie can fall in Love with Someone. It's A soulmate thing,from the beginning she called Jacob her Jacob.