Likeablilty is a hidden stat that cannot be viewed through the stats panel (but you can use the Steam achievement progress bar, it shows the current value, that is, it can decrease).
It rises with sleep, play game, delete error, and eating foods that increase it and falls with work and learn
For this stat 3 achievements are given - for 100, 200 and 500 points
Likeablilty has a limit calculated by the formula:

90 + level * 10

That is, in order to score 500, you must first reach level 41 and send the girl to play/write in a note/sleep, while it is better not to work and not study - it is rises slowly, but falls quickly. Or just give your girl an APhone 14 Pro and a GTC4090 and then give it to a pet in the game)