just need a smart plan, u want ur girl friend to see smthg inforgetable in doha why sealine hotel? some kms inside there fully equipied camps closed to the sea that belongs to some tour companies it's less cheaper than sealine beach and more interesting, before ur girl freind come arrange a booking for an overnight camping safarie, they will come pick u from doha in a 4 weel drive car and you will enjoy the drive on dunes for almost one hour, then you reach the camp there is all the facilities and soft drinks and bbq, setting around the fire, listening music, talking, playing basket on sand, shisha, swimimg, there is arabic tents where u can sleep (sleeping bags) just do it and you will like and also you will (pray for me حتدعيلي:))because of my advice to u.