How to create a sharp edge at the intersection of two surfaces?

[Ercument_Talha_Tayfu (Ercument Talha Tayfur)]

Hello,
I am currently modeling the object shown in Image 3. I am having difficulty creating the sharp transition at the intersection between the blue bottom surface and the wavy surface coming from the top. I cannot reproduce the crisp edge where these two parts meet. Could you help me understand how to achieve this?

[Lagom]

Looks like someone sketched something implausible or not thought through. Two surfaces can only meet with a crease (“sharp edge between them”) if they meet at an angle. Ask the designer to furnish a proper sketch or ask what the formal aesthetic intention really is.

[Arda_Eren_Demir]

Did you tried trim and blendsrf?