Berahino saw two second-half spot kicks saved during the 1-0 defeat to Watford on Saturday, but Pulis is confident the striker will bounce back.
The 22-year-old was twice denied from the spot by Hornets goalkeeper Heurelho Gomes as West Brom slumped to a 1-0 defeat at the Hawthorns.
Having seen a tame first penalty saved after 67 minutes, he was again kept out five minutes from time, with the result extending the Baggies' winless run to four games.
But while disappointed by the defeat, Pulis was sympathetic towards Berahino, adding he is confident the forward will bounce back.
According to the Express and Star, Pulis told reporters at his post-match press conference: "It can be a cruel game at times. Since I've been here he's always been the penalty taker and always been competent as well.
"The kid wanted to take a second one.
"If he lacked any confidence he would have walked away from it. You can't have a go at him.
"The keeper's made a fantastic save for the second one, he's got down to his left to a well struck penalty. It was a fantastic save.
"It's very disappointing for the players because I thought at times they played really well today."
But Pulis is adamant that Berahino, who has scored seven goals so far this season, will bounce back stronger.
"Good strikers miss chances and opportunities and penalties," he added.
"He'll be stronger for it.
"He's a good player and this will happen to him because it happens to us all."
Berahino reportedly apologised to his team-mates after the game, but the former Stoke boss said his side lacked an overall cutting edge in the final third, insisting they deserved more for their attacking efforts.
"It wasn't our day in front of goal. We created enough opportunities.
"Through the pitch I thought we played really well.
"We had something like 40-odd crosses, 16 efforts on goal, two penalties and we still couldn't score.
"I'm really really disappointed for the lads because quite a few of them put in really good performances today.
"Our quality with the crosses when we got in there could have been a lot better."