Please don’t make duplicate topics albeit I note the duplicate topic with a different title has been closed by you now. You can ask our helpful mod team of @DarkestKnight or @Mulberry to edit the subject header of the title for you.
There are many love demons Dantalion, Sitri, Rosier etc.
This thread lists a number of love demons : Which love demon best?
Without knowing more of the person you want to make your girlfriend it’s impossible to know which demon would be suited to you.
Do you know the woman or is she some rando passerby / a stranger?
Is there some bad blood between the two of you, in which case forgiveness may be required
In any event both scenarios are the same scenario 1 you proposed is to change the emotions of the woman and scenario 2 is making her feel passionate love for you which from the sound of things will also be changing her emotions.
Belial although predominantly used for legal matters can be used for changing mindsets. Belial does tend to have a somewhat shifting personality the first time I met him he refused to work with me, subsequently we have worked together but I only have a 50% success rate with the work I do with Belial.
Zagan is amazing at changing minds probably the closest demon I have a relationship with. He is continually working in the background to change my partner and continues to do so even though the summoning was over a year ago.
In any event keep in mind love magic is a battle of wills and is probably the most unpredictable area of magic