I search this  เล่ห์รักยาใจ means:
เล่ห์รัก = tricky love
ยาใจ = medicine for broken heart
เล่ห์รักยาใจ = the tricky love that can cure broken heart
I think this novel maybe say a man love a women,but this women do not love him.so he fell sad and never love anyone.when he meet a women,maybe this women is very cute,so can cure this man  broken heart.
I do not know why say tricky love ? maybe this women also do not love him ?