It is clear from the language that Marlow uses to describe his love for Kate in Act V that, on his part at least, his relationship with her is based on love and respect. This becomes apparent in Act V, when Kate places her father and Sir Charles as obervers as she has her final interview with Marlow in her disguise as a servingwoman. As a result, she is able to ensure that there are witnesses to testify to the depth of feeling that Marlow feels towards her. It is particularly important to note how Marlow's language in this scene differs so strongly from the scene in which he accosts her and tries to kiss her, as the following quote shows:
I will stay, even contrary to your wishes; and though you shoul persist to shun me, I will make my respectful assiduities atone for the levity of my past conduct.
Not only is his speech more formal, therefore indicating seriousness, but he also apologises to her sincerely, recognising the mistakes he made in the past. His love is shown ultimately when he kneels to Kate and is on the point of proposing before the eavesdroppers reveal themselves. Therefore the text makes clear that Marlow definitely loves Kate, and it suggests, though never states, that Kate is very interested in Marlow. Perhaps the audience is meant to assume that now she has seen the "real" Marlow she is able to love and respect him just as Marlow himself loves and respects her.