would 是will的过去时态.
would
1.用于表愿望、请求或建议的陈述之后.
例：I wish you would stay.我希望你能留下来.
2.用于有礼貌的请求.
例：would you go with me
3.表示不确定之意.
例：it would seem to be getting warmer.
would也可以表示过去反复发生的动作或某种倾向
will
助动词：将；会；愿；要
例：he will come back soon.他很快就将回来了.
he will often sit up all night.他常常熬夜.
it will be fine tomorrow .明天将会放晴.
名词：决心；遗嘱；意图；意愿；渴望；随心所欲
例：let him do what he will .让他做他想做的事情吧.
举两句歌词给你看看
would you wait for me forever
will you wait for me forever
意思：
would有请求的意思 请求“你永远等我”
will是询问 “你能永远等我么?”