There's something about you
I want to rescue
I don't even know you
So what does that mean

Leonard didn't know why but he felt that he needed to rescue Penny…Maybe he wasn't Green Lantern or The Flash but he just felt he had to protect her

Maybe I'm cynical
I'm painfully logical
You're tragic and beautiful
And that's good enough for me

Maybe he's cynical, or painfully logical, but she's tragic or maybe messy, but she was still beautiful, and that was enough for Leonard.

You're looking for a hero, but it's just my old tattoo
Tonight I swear I'd sell my soul to be a hero for you

She's looking for a hero, but Leonard is not a hero...but just for Penny, he'd be one.

Who's going to save you
When the stars fall from your sky

When it was raining he was there with an umbrella, he always protected her from rain, and If he didn't had an umbrella, he'd give her his jacket.

And who's going to pull you in
When the tide gets too high

And when they were at the beach, she almost drowned but Leonard pulled her out of the water, he is a homunculus but when it came to Penny, nothing else was important.

Who's going to hold you
When you turn out the lights

Something many people didn't know, is that Penny is scared of dark, when Leonard found out, he held her in his arms telling her that everything was going to be ok

I won't lie I wish that I
Could be your superman tonight

Leonard couldn't lie, he just wished he was her Superman, at least tonight…

Penny didn't have to worry, she has a Superman, maybe he's not the tallest, strongest, most powerful man on earth but he cares about her and he would do anything to save her. She's happy she has her own Superman, little, but still Superman.

-

That's it (: Hope you liked it :D The song's not complete…because the rest of the song didn't fit…so

Though I hate Bon Jovi, I love this song!