Does Buddha ever mention that life is full of sufferings?Is Buddhism teach us to understand sufferings?

I don't know why you ask this? I am a Christian but I know that the Buddha saw that life was full of suffering and His teachings are designed to help people have less suffering while on Earth. If you want to become a Buddhist you should read some books on Buddhism but I encourage you to become a Bible believing Christian. The Bible has all or most of the Buddha's teachings on how to have less sufferings and much, much more. The Bible can teach you how to be happy in Heaven for all Eternity after this life on Earth is over.