
Reincarnation stories confuse me because it begs the question of whether you regress to your current body's age, or whether you retain the brain that you die with. Personally I feel it's the prior, but hey it's all fantasy so they can say and do whatever they want haha.
The lack of chemistry truly is the biggest crime of the author. Like PLEASE can somebody around here write some good romance into a story if you must add it in

Humans blushing not only because of romantic feelings...
Humans can blush when drinking alcohol.
When get cold.
When exercising hard.
When get embarrassed/feeling shameful.
When being shy.
And many other moment where someone would blush.
And for this, they just finished a heavy exercise (fighting for hours).
Of course their face would blush!
Their heart be pumping them blood to increase power/speed to their martial arts movement. Blood rush to face, to neck, to whole body, but since face is the most visible part of the body and much more easily to turn colour, hence these 2 faces is blushing.
Btw, when I cover myself with blanket for couple hour to keep myself warm, my face also very visibly blushing.

I don't disagree with you. Just that in 90% of action stories if there's any blushing between a man and a woman, it's game over. Especially because he's fought hard with several men, no blushing.
The subsequent chapters have been chill though, so it doesn't look like it's going to follow the dumb formula of other stories where they want to rapidly introduce a romantic aspect.
What's with all the blushing from both? I haven't felt any connection or chemistry thus far, so it was pretty weird to see out of no where. Plus, isn't she just retaining her youth through martial arts and she's a middle aged woman? What a strange chapter