Will I still lose weight if I don't quite reach ketosis?

some lose weight only when being low in carbs, and not nessesarily in ketosis, I think it differs from one person to the other how low one must go to get into ketosis

If you want to guarantee that you get into ketosis try cutting right down to a maximum of 20-25g carbs total for a couple of weeks.

But you may well be able to lose weight on your 40g carbs anyway - you'll have to try it and see as "no one size fits all". You don't have to be in ketosis to lose weight, and you may not necessarily lose weight when you're in ketosis.
Either way you should start to see an improvement in your glucose levels though.

Use Google to find one of the low carb/keto nutritional calculators which can help you find the best ratios of carbs/protein/fats for your particular situation . Basically when you've gone low enough carb to switch your body over to fat burning mode (keto/fat adapted), to lose wieght you also need to be eating somewhat less fat than you need for energy, so that you use your body fats instead of dietary ones.

Robbity

ketosis just means fat burning - most people do that at some time during each 24 hours.
I used to lose weight if I kept under 80 gm of carbs a day, and did two lots of exercise most days. I was also running around after the family back then, ignoring the insistence that eating according to Atkins was terribly dangerous.
When I tried to do 20 gm of carbs a day I lost half a stone in three days and went very wobbly. I upped the amount of carbs I ate each day until I was losing about 1/2 a lb a day and felt just fine. We each have a level below which we lose weight - the Atkins term is CCLL for losing and then CCLM for maintenance levels. When you find out your numbers controlling your weight becomes very simple.
I found that the foods which stopped me losing weight also spiked my blood glucose - there is a carbohydrate ladder which rates carbs according to their 'clout' which is also part of the process, but it is only important if you don't keep away from 'the usual suspects' for type 2 blood glucose control.

As stated by others we are all different. I doubt that I have ever been in Ketosis but I have lost over 4 stone ( I was somewhat overweight) over about 6 months . I suspect that reducing to very low carb will lose weight quicker . I took the view I wanted to lose weight on a diet I could keep to for life so have higher carbs and try and keep around 50 to 60 whilst avoiding potatoes, grains and rice the carbs are mainly from vegetables, berries and nuts. Things which helped me to lose weight was making sure I kept protein to 0.8 of the weight I wanted to be the final weight , and drinking at least 1 .5 litres of fluid a day and keeping away from diet drinks apart from the odd treat as they make me want to eat more sweet. things and trying not to eat after 6 pm ( apart from special occasions)

I lost a third of my weight on more than 40g carbs. I didn't go very low carb until later. I have never checked my ketones. I was lucky as my weight just fell off but it was blood sugar levels I concentrated on. The weight loss was a bonus.

If 40 carbs is less than you usually eat then you probly will lose weight yes, It is said 50 carbs a day or less to show on ketostix or urine strips , some people at 40 carbs a day dont show and some do.