In my opinion, 3 to 5 months are good enough to do your best. I mean, it takes a couple of months before you attract a woman who is not initially interested in you. So I would suggest you make an effort, especially if you’re serious in pursuing her. Unless she made it clear that there’s no chance for you to be together.
As an Asian woman, part of our culture includes courting the lady and her family for months before she agrees to be your girlfriend. We don’t normally get attracted easily, unless our emotions are influenced by other factors such as social media and peer pressure.
We also value honesty when it comes to this matter. If I know from the start that I do not want this man to be my partner, I would honestly turn him down. There’s no use keeping his hopes up when he’s not really my ideal man, you know.