Thank you for your report.
The difficulty in raising the “Love” meter is by design. We’ve configured the game so that meeting specific conditions during mating makes it easier to raise the meter, but I’d prefer not to specify those conditions here.
If HEAT is at Moist or higher, I believe you should be able to complete Task 1 without any issues (in theory).
What caught my attention was that you have keep “Pain” to display either green or nothing at all.
As you mentioned, based on my assumptions, if “Pain” alternates between showing nothing and green, it should be possible to complete Task 1—albeit by a narrow margin. (Ideally, it should always show nothing.)
However, after reading your report, I suspect that the Queen’s HP is decreasing more rapidly while “Pain” is displayed as green than I had anticipated.
I plan to investigate this issue and make adjustments in the near future.