Because there are only 51 republican senators and Collins and Murkowski are guaranteed to vote no, so that means 49 votes, not counting Rand Paul who always makes a fuss about something. McCain can’t vote, so that is 48 votes. So, if you do the math, confirming isn’t automatic. I hope you understand.
Lets count the number of demorat senators in states that the President won who are up for reelection this year.