He fell first but she fell harder

• The Princess's Man (Arguably he falls first, but ultimately she definitely goes to incredible lengths to save him both in body and soul. One of the most intensely romantic couples I've ever seen.)
• Happiness (Perfect example of this trope!)
• Love and Redemption (FL is incapable of love and ML loves her for multiple tragic lifetimes. When she finally loves him back, she travels the world to find him and risks everything to save him.)
• Lost Track of Time (ML loves her from the start, she only loves his evil brother. After she returns to the past, she slowly falls in love with him. Note: the ending is implied to be happy, but a bit open. However, if you watch the bonus epilogue, it's a clear happy ending.)
• The Legends (ML loves her quietly for years, FL views him as an enemy after her return, then slowly begins to see all he's done for her. Later, when he's completely taken over by the demon in him, she saves him and risks everything to protect him. Note: the ending is a bit rushed and choppy because it was re-edited last minute but it's clearly a happy one.)
• A River Runs Through It (Possibly. ML loves her for years while she has a crush on someone else. Finally, almost too late she thinks, she loves him back.)
• Jun Jiu Ling (Arguably. ML has a crush on her when they were childhood friends to present day. While the FL has many suitors, she only falls for the ML and sacrifices a lot to save him from illness and later prison.)
• No Secrets (ML loves her for years, FL regards him as too young for her at first. Later, when he's falsely accused of murder and can't remember if he's guilty, she is the only one who believes him, works incredibly hard to clear his name, and has fallen deeply in love with him.)
• Love in Between (ML loves her for years, FL is focused on her goals and doesn't notice all he does for her. While, it's very slow burn, once she discovers the truth, she even defies the palace to save him and get him out. Note about the ending: when last shown, the ML is critically ill from poison.  In the final scene the leads' young child is shown, and you hear her talking to their father as she enters his medical clinic (and the sign with his name on it) so you know that he does indeed survive, the leads go on to have a child, and settle in a town, so it's definitely a  happy ending.)

 Akimore:

• Alchemy of Souls
• Doom at Your Service
• Why Her?
• A Business Proposal
• Strong Woman Do Bong Soon
• Weightlifting Fairy Kim Bok Joo

Thank you. I watched all of them except why her?  as i read reviews they don't have happy ending

 Shruthi:

Thank you. I watched all of them except why her?  as i read reviews they don't have happy ending

I'm pretty sure that although it doesn't have the happiest ending, it ends on a high note. Maybe it's better to call it a "good ending"?

 Akimore:

I'm pretty sure that although it doesn't have the happiest ending, it ends on a high note. Maybe it's better to call it a "good ending"?

I agree, it's a good ending! Since it's a melodrama, some really tragic stuff has happened. But I see a  positive resolution of all the heavy career, crime, and relationship issues. And I see the leads having a clear path forward, already having proved they love each other. Also, the original request is for FLs who do a lot for the ML, and her sacrifice and redemption, specifically related to him, are pretty darn impressive.