No. Not necessarily.

She's likely just having a good day, wishing YOUwould smile, so giving you the cue, or listening to George Carlin on her iPod.

If she smiles, you pass one another, and then you look back to see her looking over her shoulder at you and still smiling, THEN she thinks you're cute and you'd be a fool not to talk then.

I usually just assume she forgot her glasses that day or there is someone good looking standing right behind me.

Not always, but one way of finding out is to up the ante a bit.

I'm incredibly shy as well, but a decent approach is just to say hi. If she says hi back, that can be a good sign, but it's the particulars (tone, body language, etc.) are where the real meaning is. She can say hi for the same reason that people smile: just to be friendly without any other discernible meaning. If she starts a conversation, obviously that is even better, but it still doesn't mean she's attracted to you.

Multiple looks and smiles are, as Rev Smith said, a really good indication of some sort of interest.

However, being able to start the "you're cute, no you're cute" dance cycle is a good thing. You'll know pretty quickly whether she's into you or not.

She might think that or she might not. Only she would know.

Maybe she's had a crush on you for years and she's smiling because you're finally noticing her as she walks by. Or maybe she noticed that your fly zipper is down and seeing that has put a little joy in her otherwise dreary day. Maybe she's smiling because she's listening to TAL and Ira Glass just said something amusing at the exact same time she happened to be looking at you. Or maybe she recognized you as the guy who bought not one, not two, but seven different books about pugs at the used bookstore the other night. Maybe seeing you triggered fond memories of a similar looking guy she lived with for five years. Or maybe she's impressed that someone is actually able to look good with that haircut. Maybe she got just a raise at work. Or maybe she just moved here and thus she smiles at every single person she passes on the sidewalk.

There are hundreds if not thousands of reasons as to why she may have smiled at you. Trying to figure out what people are thinking may make you insane. Communicate with them directly (in a good way) if you truly want to know (and even then you may not find out the truth).

Just say hello, howdy, or how ya doin. She'll either say something back or she won't, but either way it will give you more information than you get by hiding in your shell.

I swear to god nobody of any gender or persuasion in this town has matured beyond middle school level relationship skills.

If a girl is over a certain age, there's usually a reason they're smiling if it's towards the opposite sex. Sometimes younger girls smile out of nervousness... But it never hurts to smile back and say hello.

If you're about to walk past each other, she might just be being polite. However, if she smiles at you from across the street, the odds are good she thinks you're cute. Sadly though, that might not mean she wants to talk. She might just be enjoying the view, and by view, I mean, your ass.

I don't know... Here in Seattle, it's pretty normal for people to avoid eye contact on the street. I tend to think that if a girl is going out of her way to make eye contact and smile at you, there's a good chance she's interested. It's worth a shot to say hi.

Like others have said, she could be smiling for a million reasons, and she might or might not even be smiling at *you.*

Only she knows, and the only way you can find out is smile back. Say "good morning" or nod and say "hi there." If you're heading in the same direction, maybe you can strike up a conversation.

Maybe.. She might be having a good day, maybe you remind her of someone else, maybe she likes something you're wearing, maybe she likes your smile, or it could be not related to you at all.

I agree with Rev smith, if you catch here double checking you over her shoulder, then it's a defenite yes. Granted if she's shy too, she might run away when you try to approach.

nod and smile politely.it weirds me when people are moving and i am moving and they try to initiate a conversation. but if you are both stationary, striking up a conversation would be fine. but dont get bummed if the girl ignores you.

i smile and say hi to passing strangers all the time. even the ugly ones. it's the polite thing to do, i'm told.