Can you marry the Witch Princess in harvest moon island of happiness when your a girl?

Yes, but there are many difficult requirements.

To marry the Harvest Goddess you must:

Upgrade your house

Buy the Large Bed

Have a Red Heart with her

Be in Year Five or Later

Ask Carter's permission during Confessional Times

Catch all types of fish

Ship one of every item

Find all items hidden in the Mines

Collect all nine Goddess Jewels

After all of that you can propose with the Blue Feather.

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