Omitting the MC, a true mother would accept after speaking as adults a relationship with conditions, establishing that her priority would be the son and in case he does not support her to raise the child that then there would be no relationship, since she wants stability and a reliable partner (this is a perspective of so many and there are mothers who don't care about the above but want a relationship to free themselves from stress).
Here again omitting the comedy, basically she rejects because she possibly misunderstood the words of the MC (if he really did not mean what he said) about the son, but there is no need to highlight his employment status when she is not in good position either and raising a child in developed countries and more in Japan is expensive (although I think there are support programs for infants).