Ask a friend to exercise with you. You can maybe go for a swim every week to begin with? Swimming is nice, healthy and especially: you will not get an injury easily.
If you ask a friend (or ask your SO?) to join you, you will not give up that easily (that's what I've done, me and my best friend are swimming every week now
Then, as for losing weight with a "diet". I don't really believe in diets anymore, since you will probably gain weight again if you stop the diet... and I don't think I will ever have the "courage" to maintain a diet for the rest of my life.
There are small things you can change though, which you can keep doing for the rest of your life without feeling like you're on a diet.
1) replace unhealthy snacks by more healthy (but still tasty) snacks: you can eat crackers, fruit (I'm getting addicted to mango and bananas
), vegetables (remember those small sweet tomatoes!), soup, ...
2) my secret (not so secret anymore) weapon: an iced tea mix I make myself. With this "recipe" I lose way more weight than when I'm drinking water... (and waaaay more than when I'm drinking soda, but that's obvious...).
What do you make? 3/4 green tea that you leave to cool down (green tea makes you lose weight and is healthy overall), 1/4 light cranberry juice (you can also add sweetener, but don't add sugar since that will give more calories). It's tasty like soda is and helps you lose more weight than when you drink still water.