Just take the word 'tone' out of your vernacular when it comes to exercise. There's no such thing as 'toning'.
Looking good in a pair of snug jeans starts at your shoulders, moves through your core past your waist, and down your hips. Working your obliques won't do you any good because working them isn't going to remove the fatty layer above them.
If I were you, I would implement a good diet of 'clean foods' that aren't processed, are generally whole, and are low in simple carbs. Then, I would begin a regular routine of HIIT cardio (example: alternate between sprinting for 20 seconds & walking for 40 seconds for 30 minutes a day, working your way up to sprinting 1 minute walking 1 minute and alternating like that) while also lifting in a split routine for 5 days a week.
Lifting weights won't make you bulky.
Lifting weights is good for your bones.
Lifting weights isn't going to make you look like She-Hulk.
Lifting weights will increase your resting metabolism, causing you to ultimately burn more calories.
Simply doing crunches won't work. Simply changing your diet will help a little bit.