Doubts arise because of an ...

Doubts arise because of an absence of surrender.
 Ramana Maharshi

Quotes from the same author

What exists in truth is the Self alone. The world, the individual soul and God are appearances in it. Like silver in mother-of-pearl, these three appear at the same time and disappear at the same time. The Self is that where there is absolutely no 'I thought'. That is called 'Stillness'. The Self itself is the world; the Self itself is 'I'; the Self itself is God; all is Siva, the Self.
 Ramana Maharshi
How to get rid of the mind? Is it the mind that wants to kill itself? The mind cannot kill itself. So your business is to find the real nature of the mind. Then you will know that there is no mind. When the Self is sought, the mind is nowhere. Abiding in the Self, one need not worry about the mind.
 Ramana Maharshi
If a man considers that he is born, he cannot avoid the fear of death. Let him find out if he has been born or if the Self has any birth. He will discover that the Self always exists, that the body that is born resolves itself into thought and that the emergence of thought is the root of all mischief. Find from where thoughts emerge. Then you will be able to abide in the ever-present inmost Self and be free from the idea of birth or the fear of death.
 Ramana Maharshi
The grace of the Guru is like an ocean. If one comes with a cup he will only get a cupful. It is no use complaining of the niggardliness of the ocean. The bigger the vessel the more one will be able to carry. It is entirely up to him.
 Ramana Maharshi
Under whatever name or form we worship It, It leads us on to knowledge of the nameless, formless Absolute. Yet, to see one's true Self in the Absolute, to subside into It and be one with "It, this is the true Knowledge of the Truth.
 Ramana Maharshi