Is it true that one who put ash to their forehead will go for Kailasa after death?
This belief is trusted by smartha brahmins community
Your question itself answers that this is a belief. If you have true faith in this belief, follow it. But is it the only criteria? Definitely no.
Realization is what separates us mortals from the one residing in Kailasa. To attain realization or libertaion, you must follow 8 fold paths in Yoga of patanjali (http://en.wikipedia.org/wiki/Yoga_Sutras_of_Patanjali#The_eight_limbs_of_Yoga) and attain Nirvikalpa samadhi. This is possible only under a guidance of a guru. Hence first find a guru for your as per your spiritual and materialistic needs.
@Mithun - There is a hidden meaning in this on putting ash in forehead. It's not directly Ash, then if that's the case many would have gone to Kailash by now.
Here Ash symbolically represents your sexual energy which is white. You need to raise your sexual energy and stop it inbetween the eyebrows which is called இமயமைலை. Eyebrows in Tamil called = இமை and center point between that is மையம் and joining these two in Tamil will give you Himalayas where Lord Shiva resides.
To know more about the God, Atman, you need to explore our Indian languages than these English. Indian languages has many hidden meanings and things which will make you know God.