So I drove up to my apartment building (only students) and saw a girl trying to fix her bicycle at our building's entrance. After parking my car and walking back she was still struggling so I thought I'd offer some help just to be kind and of course for the small talk challenge. I asked what the problem was and she explained it to me, but turned down my help. I feel like I asked it in such a way (something like 'Do you want me to help you or can you handle it alone' -not literally, English isn't my main language-) that she just politely turned my offer down, because I saw that she obviously didn't know what she was doing.

Therefore my question for future situations like these: how would I offer / ask (ie. help, but could also be a drink or something) things in such a (more alpha) way which makes accepting / agreeing more likely.