If they dont reject baptism, they still can be saved.
Catechism of the Catholic Church
1635 According to the law in force in the Latin Church, a mixed
marriage needs for liceity the express permission of ecclesiastical
authority. In case of disparity of cult an express dispensation
from this impediment is required for the validity of the marriage.
This permission or dispensation presupposes that both parties know
and do not exclude the essential ends and properties of marriage;
and furthermore that the Catholic party confirms the obligations,
which have been made known to the non-Catholic party, of preserving
his or her own faith and ensuring the baptism and education of the
children in the Catholic Church.
By law, if u marry a catholic, the children WILL be
catholic.
