HI, Guess it is a 1.3 Flair.
1. Check the voltage of battery while you are cranking. 4 years is quite a good time for a new battery.
2. Are you using the right gear? 30 degrees is way too exaggerated. A proper road can have only 10 - 15 degrees (18 - 27%) of inclination max and that is what passenger cars are tested for. For 30 degree slopes, better buy an SUV. Slope Percent to Angle Degrees Conversion Calculator
Do you hear misfires? Though might not be the case, the ignition coil is notorious to fail often. Get that checked with a competent mechanic.
Go through this, just for knowledge. https://en.wikipedia.org/wiki/Grade_(slope