What can we say about Solmes, the dude who circles around trying to get some Clarissa scraps? The guy may be old, ugly, and a real pain to be around, but at least he knows his strengths. That is to say, Solmes is rich. Not only is he rich, but he knows that wealth can usually accomplish more than youth, beauty, and smarts put together. And he plans to use his massive stores of moolah to get himself a wife.
Wait, scratch that. Solmes is also perfectly happy to throw Lovelace under the bus to get Clarissa on his good side. "I have something to communicate to you that concernes you much m if you be pleased to admit me to youre speech," he writes to Clarissa. Let's ignore for the moment that Solmes is about as good at telling apart "yours" and you'res" as the average YouTube commenter. You can practically hear his self-complacency smacking through his single correspondence to Clarissa.
It's also significant that Solmes is so bad at writing, since he's trying to woo Miss Clarissa, the queen of letters. If she weren't totally disgusted at his bad personality, she'd definitely have a hard time getting over his lack of epistolary style.