Simply applying partial bold style between tags inside UILabel class category. Usage: #import "UILabel+BoldTag.h" // import the category [lbl_player setText:@"You [b]want to play[/b]"]; [lbl_player renderBoldTag]; // render bold tag

UILabel+BoldTag.h

//
//  UILabel+BoldTag.h
//
//  Created by Guvener Gokce on 8/2/13.
//  Copyright (c) 2013 Gladly Interactive All rights reserved.
//

#import <UIKit/UIKit.h>

@interface UILabel (BoldTag)
-(void)renderBoldTag;
@end

UILabel+BoldTag.m

//
//  UILabel+BoldTag.m
//
//  Created by Guvener Gokce on 8/2/13.
//  Copyright (c) 2013 Gladly Interactive All rights reserved.
//

#import "UILabel+BoldTag.h"

@implementation UILabel (BoldTag)

-(void)renderBoldTag
{
    if ([self respondsToSelector:@selector(setAttributedText:)])
    {
        
        UIFont *boldFont = [UIFont boldSystemFontOfSize:self.font.pointSize];
        
        // Create the attributes
        NSDictionary *subAttrs = [NSDictionary dictionaryWithObjectsAndKeys:
                                  boldFont, NSFontAttributeName,nil];
        
        
        
        NSString *aText = [NSString stringWithFormat:@"%@",self.text];
        NSRange start = [aText rangeOfString:@"[b]"];
        NSRange end = [aText rangeOfString:@"[/b]"];
        if(end.location > 0)
        {
            aText = [aText stringByReplacingOccurrencesOfString:@"[b]" withString:@""];
            aText = [aText stringByReplacingOccurrencesOfString:@"[/b]" withString:@""];
            [self setText:aText];
            
            NSMutableAttributedString *attributedText = [[NSMutableAttributedString alloc] initWithString:self.text
                                                                                               attributes:nil];
            
            NSRange boldRange = NSMakeRange(start.location, end.location-start.location-3);
            
            [attributedText setAttributes:subAttrs range:boldRange];
            
            [self setAttributedText:attributedText];
        }
    }
}

@end