Could i make a photo look like this with my Nikon d3100?

If yes with what lens?

Added (1). I have the kit lens 18-55

Which lenses do you actually HAVE?

The photo is very nice, but nothing amazing. Most lenses would be capable of that one.

Large aperture, a bit of zoom, and bingo - you have that nice looking shallow DOF.

Yes you can! Even if you are using the kit lens. Just read some guides/techniques online on photography.

Shoot in A (aperture priority), selecting the largest f/stop you have. Let's assume you have the 18-55mm f/3.5-4.5 kit lens - use f/3.5.

Move back and shoot at the maximum focal length. (55mm?) This, along with the wide open aperture give you the shallow depth of field, putting the background into a nice artistic blur.

Use a low ISO, perhaps ISO 200.

Use white cardboard or refrectors to throw some lighting from the side. You'll notice how even the lighting is. This can also be achieved if you find some nice outdoor indirect lighting where there are no harsh shadows. Using a flash requires off-camera flash equipment and techniques that we won't go into here.

If you have the patience and skill, switch to manual focus and focus on the eyes.

All of this can be made easier with a Nikon 35mm f/1.8 or Nikon 50mm f/1.8 or f/1.4 lens. The 50mm f/1.8 will only work on your D3100 in manual focus, but the other two will autofocus perfectly.

Hope this helps.

Use AF-S mode and single point AF. This way you can center on the eye and press the shutter half way and lock focus on the eye. This is important in portraits. If you don't use single point focus then the camera may focus on the nose for example.

Use the widest aperture for you lens. Set aperture priority mode (normally 'A' or 'Av' on the dial) and set the value to the smallest number possible (on a kit lens this is likely to be f/3.5). Set the focal length to 55mm (i.e.zoom in!) and step back until you've framed the subject how you'd like it. Not only does 55mm offer a more flattering image for portraits then wide-angle but the combination of focal length, distance from subject and wide aperture will help to throw out the background.

The subject is very bright in the example and you can do this in a few different ways. 1.fill-in flash, although you may get some unwanted shadows. 2.use a reflector to bounce light back onto the subject. They're relatively cheap and the 5-in-1 type come in handy with white, black, silver and gold covers. 3.exposure compensation. Look for the EV setting on your camera and finally 4.post processing. You could brighten it up afterwards in Photoshop or similar.

Put the camera into A or M mode. Set the ISO to 200.

Yep, zoom into 55mm, move back to get the composition you want (don't zoom, physically move closer or nearer) use the pop up flash for fill light, perhaps even dial in +1ev of flash exposure compensation.

Set an aperture of f5.6 (the widest your lens will allow)
Set AF mode to single shot.
Set AF point select to centre point.

Place the centre point over your subjects eye, half press for focus confirmation, recompose with pressure held on shutter, then full press when ready.

Your image will not be as blurred as in this image, you may want to get a faster aperture lens such as the Nikon 50mm f1.8 or f1.4, or the 35mm f1.8.

Yes you can. Get close, change utilize your depth of field and get a BIG f/stop opening. Simple.

Yes but in all honesty you should get a faster lens than the 18-55mm as the bokeh (blur in the backround) will not be at the quality of the image you showed. A50mm f1.8 or 35mm f1.8 is a much more suitable lens for doing pictures like this. (In the knowledge she shoots nikon D3 bodies she probably was using a 24-70mm f2.8)

To do a picture like this (with any lens) you will need to be close to your subject and use your widest aperture or f-stop (f/1.8 - f/5.6). I recommend using either the Aperture priority or Manual dial modes to set it as other modes will choose the aperture for you. Make your ISO is set to 200 and your af is set to single point AF.