I’m executing negative scenario for Jmeter API automation,

Scenario: Running negative scenario and validation following,
Status Code = 400
Validation Message = X

Output :
Status Code:400
Validation Message = Y

JSR22 Assertion failed but not the main sampler,

I’m using below code in JSR223 Assertion,

def errorvalue = vars.getObject("errorvalue_1")
log.info("Value of Json Response Error Message is ::"+errorvalue)

def experror = vars.get("ErrorMsg")
log.info("Error value is ::"+experror)

if(errorvalue.toString().equals(experror.toString())){
 
    log.info("Error Message is matched")
    AssertionResult.setFailure(false)
     AssertionResult.setFailureMessage("Error Message is matched")
}else{
    log.info("Error Message is not matched")
    AssertionResult.setFailure(true)
     AssertionResult.setFailureMessage("Error Message is not matched")
}

Please help me to make it fail main sampler.