I have been trying to go on a date with Haley but I'm not getting any mail from her to go on a date I have tried for a month for it to happen but it won't work.
Mail? For a date? This isn't anything the game has ever had in the past. Is his a new 1.3 Beta addition? I've never seen any mail from Haley at any heart-level in the game, and all the 'dates' with her are just heart events unlocked at various friendship levels. What 'date' are you referring to?
I was trying to learn how to get married and i watched a video on how to get married and the video said that you need to get the character to 10 hearts then they send some mail that says to meet them in the saloon and you go there in a date. But I'm not getting any mail. Here's the link if you have no idea what I'm talking about:
The Saloon date is only for Alex, and even then it's not a requirement for getting married. All of the marriage candidates have cutscenes at 10 hearts, though, and many of them won't happen if you've already married the character, so if you want to make sure you see it you might want to look at the "Heart Events" section of the character's wiki page to see how. For Haley, that would be here: https://stardewvalleywiki.com/Haley#Ten_Hearts