How could Forrest believe that was his son?
Jenny was the biggest ho east of the Mississippi.
shareWell she was with Forrest for a while and I think she was done with her promiscuous ways.
shareJenny, in his eyes, was perfect. That's why it's a beautiful love story
shareThat was one of the saddest and most messed up parts. Also, did he really have sex with her? I feel like he got a handjob and premature ejaculated. I don't think there was penetration.
shareThe hand job was when he visits her in college. Little Forrest is supposed to be conceived later when Jenny is staying with Forrest after his mom dies. Jenny comes to him, says she loves him, and the two of are shown in bed together. Jenny then leaves the next morning.
Jenny had been staying with Forrest for a while at that point, so let's assume she hadn't been with anyone else during that time. And if the reason she leaves is because she realizes she loves him too much to marry him before she can live on her own two feet, loving herself (this is not explicitly stated, but it makes sense), then she probably wasn't with anyone else afterwards either.
makes sense
share
Maybe if people would actually watch the movie instead of making silly comments, they would have seen that Forrest was shown to be the father of little Forrest.
The short answer? Because Forrest, with his childlike innocence, always took people at their word and believed Jenny when she said he was the father.
The precise answer is a bit more in depth. Jenny shows up at Forrest's house. She lives for a while there, and we don't ever see her with any other man. We don't know exactly how long she stays, but I'm going to go out on a limb and say it's at least long enough to know that she wouldn't have been pregnant with anyone she had been with before she arrived.
She sleeps with Forrest the night before she leaves. We don't know exactly where she goes at this point. We know she eventually ends up in Savannah, but not whether she goes straight there or stops at other places first. The next time we see her, she's watching Forrest on the news because of his running. She's at work at this point. We think this is a throwaway scene, shown just to prove how big of a story Forrest's running was, but it actually tells us something about her. Up until this point, Jenny has modeled for a porn magazine, performed at a strip club, panhandled, and done who-knows-what with who-knows-whom. This time, though? She's working as a waitress. Maybe not the most glamorous job out there, but certainly respectable. For the first time in her life, we see Jenny doing something to support herself that provides a regular income and doesn't involve drugs, sex or prostitution.
We don't know if this is before or after Little Forrest was born. Jenny is not noticeably pregnant. But the scene shows that she's turned her life around. So we don't just have Jenny's word that Little Forrest is Forrest's son. The cinemaphotography and directing tell us this too.