Being pregnant is hard already and it would be much harder if the father won’t accept or acknowledge the baby you’re carrying. One positive way to be sure is through paternity test.
It may be harsh but it is a very smart and responsible act also to know the real deal and know your options if you don’t know what you’re getting into. Because having a baby is not simple, you have to be mentally and spiritually ready because you will be the one responsible for that child future but I only read about this paternity test in books that I read. But I can very well say it, that this is the fastest way to know the dna of a child.